Miscarriage & Recurrent Implantation Failure Resources
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Miscarriage & Recurrent Implantation Failure Resources
Chronic inflammation and Implantation Failure and Miscarriage
Before we can understand chronic inflammation and its important role in reproduction, we must first understand what inflammation is.
What is inflammation?
Inflammation is the body’s attempt to protect itself against infections, irritants and damaged cells. Inflammation is part of the body’s immune response. Initially, inflammation is beneficial. For example, when your body is trying to fight off an infection from bacteria. However, sometimes inflammation can cause further inflammation; it can become self-perpetuating even after the initial cause is gone. In this situation, inflammation can be harmful.
Acute versus chronic inflammation
Acute inflammation starts rapidly and quickly becomes severe. Signs and symptoms are only present for a few days, but in some cases may persist for longer. There are 5 main signs and symptoms of acute inflammation:
- Pain – Chemicals that stimulate nerve endings are released which causes pain.
- Redness – Increased blood flow to the affected area causes the red appearance
- Warmth – Increased blood flow to the affected area also results in warmth locally
- Swelling – caused by the leakage of fluid from the local blood vessels
- Immobility – this mostly applies to inflammation in joints
Acute inflammation is generally easily to recognize and treat.
Chronic inflammation means long-term inflammation, which can last for several months and even years. It can result from the failure to eliminate whatever was causing an acute inflammation (persistent bacteria), a chronic irritant of low intensity that persists or when the immune system attacks healthy tissue mistaking it for harmful pathogens.
Chronic inflammation may be difficult to diagnose and effective treatment is often unknown.
Chronic Inflammation of the uterine lining
Inflammation is an increasingly recognized factor contributing to reproductive dysfunction, including several common causes of infertility such as pelvic inflammatory disease, polycystic ovary syndrome, obesity, endometriosis, and recurrent pregnancy loss. Recently, chronic inflammation affecting the uterine lining has been of special interest. This is called chronic endometritis.
What problems does chronic inflammation of the uterus cause?
The uterine lining is responsible for developing the ability to allow an embryo to implant. Estrogen and progesterone production from the ovaries induce the changes in the uterine lining that are necessary for implantation. The changes that occur in the uterine lining are extremely complex and not well understood. Some studies have identified chronic inflammation in women with implantation failure. It is also believed that inflammation in the uterine lining may increase the risk for a miscarriage.
How can chronic inflammation of the uterus be diagnosed?
Blood tests for chronic inflammation
There are some blood tests which are general, non-specific markers of inflammation. One marker is called the erythrocyte sedimentation rate (also known as ESR or “sed rate”). The sed rate is not very useful when studying reproductive age females because it is affected by estrogen levels. Another marker is called C Reactive Protein or CRP. CRP is not affected by hormone levels so is a much more liable indicator of inflammation in women. Very high levels of CRP (>10) are usually an indicator of an acute infection. Moderately elevated levels can be an indicator of low grade chronic inflammation.
Examination of the uterine lining
The uterine lining can be visualized directly by inserting a fiber optic telescope into the uterine cavity. This is called hysteroscopy. Sometimes, chronic endometritis can be diagnosed be diagnosed by this method. For example, the presence of micropolyps is a reliable indicator of chronic endometritis. These are abnormalities that will not show up on other types of imaging such as an HSG or HSN.
Hysteroscopy can also be used to obtain a sample or biopsy of the uterine lining that can be viewed under a microscope. In the uterine lining, one of the types of white blood cells which is a hallmark of chronic inflammation are the “plasma” cells. Plasma cells can be seen by looking at a piece of the uterine lining under a microscope. However, due to the presence of other similar looking cells, it is not always easy to determine the presence of an abnormal amount of plasma cells. Plasma cells have a marker on their surface which is called CD138. It is possible to stain a sample of endometrial tissue so that the CD138 stands out. This is a more reliable method to diagnose chronic endometritis.
How can you treat chronic inflammation?
If a specific cause for the inflammation can be identified then treatment of the cause should cause resolution of the accompanying inflammation. For example, if a bacterial infection is found, treatment with antibiotics can be tried.
Recently, a study found an increase in the pregnancy and live birth rates when women with mildly elevated CRP levels were treated before they got pregnant with low dose aspirin. The improvement was not seen in obese women, however.
In study in bovines also found that exposure to platelet rich plasma (PRP) would suppress the production of some of the proteins produced in the uterine lining as a result of inflammation.
Does antibiotic treatment for chronic endometritis really work?
A recent review of several studies looking at antibiotic treatment of chronic endometritis showed that women who had evidence of a cure (repeat biopsy showed the inflammation was clear) had a six fold greater chance for an ongoing pregnancy or live birth compared to women with persistent chronic endometritis.
Miscarriage
Miscarriage is the loss of a pregnancy after conception and implantation has occurred.
Miscarriages can be classified in a number of different ways. The most commonly used system involve how the pregnancy was verified before the loss was identified.
Biochemical pregnancy; Biochemical miscarriage, Chemical pregnancy, Early miscarriage
This is a miscarriage that occurs after a positive pregnancy test but before a pregnancy could be seen on ultrasound.
Clinical miscarriage, Clinical pregnancy
A miscarriage that occurs after or at the same time that it is seen on ultrasound. This is a very broad group. Some very early pregnancies can be detected by sensitive ultrasounds. There are four subcategories of clinical miscarriage that depend on what features were seen on the ultrasound:
- Gestational sac only
- Gestational sac and yolk sac
- A fetus is seen
- A fetus is seen with a heartbeat
Missed miscarriage, Missed abortion
A missed miscarriage is determined when an ultrasound shows a pregnancy is nonviable and the measurements or features suggest that it occurred a period of time before the ultrasound. For example, an obstetrician is unable to hear the fetal heart beat at 12 weeks gestation. An ultrasound is performed and the fetus is measured but it corresponds to an 8 week gestation.
Threatened miscarriage, Threatened abortion
Any bleeding that occurs in the first twenty weeks of pregnancy is defined as a threatened miscarriage. Approximately 1/2 of these pregnancies will go on to miscarry. However, if ultrasound has previously shown a fetus with a heartbeat a much smaller percentage (1-5% depending on the age of the female) will miscarry.
Incomplete miscarriage, incomplete abortion
A miscarriage that is in progress. Some of the fetal or placental tissue has passed but not all of it. Generally, the cervix is dilated.
Completed miscarriage, completed abortion
A miscarriage in which all of the fetal or placental tissue has passed.
Recurrent Implantation Failure
Recurrent Implantation Failure is a term that encompasses the frustration and uncertainty experienced by individuals who have undergone multiple fertility treatments without achieving a viable pregnancy. As we unravel the mysteries surrounding recurrent implantation failure, we will explore its potential causes and the latest advancements in fertility diagnostics that can offer renewed hope to those facing this formidable hurdle.
Window of Implantation
An important question in the treatment of infertility with IVF is this – When is an embryo able to implant into the uterus? If a normal embryo is placed into the uterus too early or too late based on its stage of development, then implantation will fail. This is known as IVF failure or implantation failure. For many years, it was believed that the “window of implantation” was a small time frame that occurred a fixed number of days after ovulation. Recent studies have shown that for some women – this may not always be true.
Before ovulation, while an egg is developing, the ovary is producing the hormone estrogen. This is called the follicular or proliferative phase. Estrogen causes the uterine lining to thicken. If an embryo were to be placed into the uterus during this time, it would not be able to implant or produce a pregnancy. After ovulation, the ovary produces the hormone progesterone. This is called the luteal or secretory phase. Progesterone causes numerous changes in the uterine lining that allow an embryo to implant. However, it seems that there are only a few days during the secretory phase in which the embryo can implant. This is known as the window of implantation.
How do scientists determine the days that the uterus is able to allow implantation? Many types of tests have been tried. The earliest attempts involved looking at the uterine lining under a microscope. Definite changes can be seen under a microscope in the uterine lining as it goes from the proliferative to the secretory phase. However, detecting the very subtle changes needed to distinguish a receptive uterine lining is very difficult. The pathologists who view the uterine lining under the microscope will often have different assessments from one another. Stated another way, microscopic analysis of the uterine lining is not accurate or reproducible. Another type of test involves looking at specific “markers” in the uterine lining. The cells of the uterine lining have a large number of structures on their surface. It was hoped that there might be a specific marker that would be present only when the lining was receptive and not at other times. The most popular of these markers is called beta-3 integrin. While there was initially great hope for the use of these marker tests as indicators for the window of implantation, they have failed to improve the outcomes in IVF cycles.
Endometrial receptivity array
Developed in 2020, the endometrial receptivity array uses some very sophisticated technology which measures the amount of RNA that the cells of the uterine lining produce.
Remember, each cell in the uterine lining has a nucleus which contains the genetic material known as DNA. DNA is the coded blueprint for the instructions that a cell needs to carry out its function. For example, if a cell’s purpose is to make a certain protein, the DNA contains the code for how to make the protein. The code is “translated” into a slightly different form called RNA and the RNA tells the cell which amino acids to combine to make the protein.
The uterine lining cells make more of a certain type of RNA at one time of the cycle and less in another time of the cycle. Scientists have used powerful computer chips to look at the amount of RNA produced at different times of the cycle. Then, using computer algorithms, they could detect patterns in the RNA production. Some RNA levels may not correlate with the window of implantation at all. Other types of RNA may be present in higher amounts and some may be present in lower amounts. In total, scientists have found 138 types of RNA (so far) that help in determining the window of implantation.
This endometrial receptivity array is very reproducible. Studies were done on patients where they took two samples at the same time of the cycle several months apart. Most often, the results of the tests were the same.
The most interesting part of the endometrial receptivity assay is that it has identified that some women might have a receptive uterus at an earlier time than expected and some might be receptive at a later time! Infertility specialists can then use this information to change the time that embryos are placed into the uterus so that it matches up better with the window of implantation!
How commonly is an abnormal test found?
In studies of women with recurrent failed IVF cycles – about 25% of the women were found to have an abnormal ERA result. In infertile women without a history of recurrent in vitro fertilization failures, about 12% of the women were non-receptive.
Of those women with a non-receptive uterine lining, most (85%) were found to have their window of implantation shifted later in the cycle. These women were said to be pre-receptive. The remaining 15% had their window of implantation shifted earlier in the cycle, these patients were called post-receptive.
How do you correct these problems with uterine receptivity?
There are some case reports and small studies in which doctors changed the timing of the embryo transfer according to the results of the endometrial receptivity assay. One such study looked at women with recurrent IVF failures using donor eggs (which means that all of the patients had high quality embryos to transfer). These patients had failed in anywhere from one to six previous attempts. Most did not become pregnant, a few became pregnant but miscarried – none had achieved a live birth. Doctors then changed the time of the embryo transfer based on the results of the endometrial receptivity assay and found that 67% achieved an ongoing pregnancy.
This was very encouraging evidence that this may be a useful test. However, as more data was collected, and larger and better studies were performed, researchers found that adjusting the time of the transfer was not improving the chance for pregnancy or live birth. As a result, in 2022, the ERA test is no longer recommended for people attempting pregnancy with IVF
How if the test performed?
The endometrial receptivity assay is performed by obtaining the tissue from the uterine lining at a very specific time. This can be done in one of two ways:
1) If a woman ovulates, she can use a home urinary ovulation predictor test to detect the LH surge. This is considered day 0. On day 7, she will go to the fertility doctor for the test.
2) Another method is to use medications to prepare the uterine lining using the hormones estrogen and progesterone. This is the method we usually use for performing a frozen embryo transfer cycle. The day the progesterone is started is day 0. The test is done on the fifth day after that.
On the appropriate day (using either method), the doctor or nurse practitioner will perform an endometrial biopsy. First, a speculum is placed into the vagina so that the cervix (opening of the uterus) can be seen. The cervix is stabilized and then a catheter (like a thin, flexible plastic straw) is advanced through the cervix into the uterine cavity. A plunger in the catheter is withdrawn. This creates suction in the catheter which draws endometrial tissue inside the catheter. The catheter is then removed.
The results are available in about three weeks.
At this time, the ERA is no longer a recommend test.
Causes of Miscarriage
Unfortunately, miscarriage is a common problem. About half the women in the U.S. will have at least one miscarriage at some point during their reproductive lives. Even worse, about 5% of women will experience two miscarriages and 1% will have three or miscarriages. These women are said to have recurrent miscarriage or recurrent pregnancy loss. Extensive diagnostic testing is performed in couples having recurrent miscarriage but about half the time, no specific underlying cause is found. In this article, we explores some common and uncommon known causes of miscarriage.
Embryo Chromosomal abnormalities
The vast majority of miscarriages are caused by abnormalities in the number of chromosomes contained in the embryo. Human beings normally have 23 pairs of chromosomes (a total of 46) Very often embryos will have too many or too few chromosomes. These abnormalities are called aneuploidies. The older a woman is when she becomes pregnant, the greater the chance for aneuploidy and the greater the risk for miscarriage.
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Sometimes, when evaluating a woman for the cause of miscarriages, the physician may attempt to obtain fetal or placental tissue for chromosome analysis. In the past, a procedure called a D&C (Dilation and Curretage) was performed to obtain the fetal tissue. However, a D&C will obtain both the fetal cells (wanted) and the mother’s uterus cells (unwanted). A newer, more accurate method for obtaining fetal cells is to use a hysteroscope to direct the physician to where the fetal cells are. This is called fetoscopy or embryoscopy.
The tissue obtained would be sent to a laboratory which would try to grow the cells in the tissue and then evaluate them for chromosome abnormality. This process is known as karyotyping. Unfortunately, this method had several problems. Sometimes the cells wouldn’t grow so a chromosome analysis couldn’t be performed. In other instances, the chromosome analysis results would be that of a normal female. When this happens, it is impossible to determine if the result is from the fetal cells or the cells of the mother’s uterus. If the mother’s cells get analyzed by mistake, it is called maternal cell contamination or MCC.
More recently, a new type of analysis has begun replacing the standard karyotype. This new analysis to perform a chromosome analysis is called a microarray. Microarrays do not depend on growing cells so a result can be obtained almost 100% of the time. It is also possible to determine whether the results are from the fetus or mother so maternal cell contamination can be ruled out.
When a chromosome analysis is performed, about 70-80% of the miscarriages will be found to have aneuploidy as the cause.
The actual percentage may be even higher. Because of maternal cell contamination, the laboratory can’t tell the difference. When the time comes to evaluate the chromosomes, the result will appear to be results from a female with a normal number of chromosomes. However, it is impossible to determine if this was from the fetus or from the mother.
Many times, doctors or other health professionals will tell a woman that this means the miscarriage was not caused by a chromosomal abnormality. This is incorrect. In fact, when more sophisticated means are used to obtain and analyze the fetal tissue, such as microarray, it has been proven that most of the time when the result reads “normal female” it really is just missing the fetal abnormality and is looking at the mom’s chromosomes instead.
Treatment of miscarriages due to fetal chromosomal abnormalities
There is no treatment that will prevent embryos from having chromosome abnormalities. The older a woman gets, the higher the chances that an embryo will have an abnormal number of chromosomes. This is why women have a higher miscarriage rate as they get older.
However, using a technology known as preimplantation genetic screening also known as PGS or CCS, we can now identify embryos with chromosomal abnormalities during an In vitro Fertilization cycle. By avoiding those embryos that have abnormalities, couples can reduce their risk for a miscarriage caused by chromosomal abnormality.
Otherwise, there is no way to treat a pregnancy that already has been established if the embryo has an abnormal number of chromosomes. This is an extremely important point! If an embryo is abnormal, then no amount of bed rest or progesterone or medications or herbal supplements is going to affect the outcome. Not all embryos with chromosomal abnormalities will miscarry. Some can go on to be live born babies. These babies however, will be born with birth defects such as Down’s syndrome or other syndromes depending on which chromosomes are extra or missing.
Parental chromosomal abnormalities
Less commonly, the male or female parent may have a different type of abnormality in their own chromosomes that causes miscarriage in a fetus. This type of chromosome abnormality is called a translocation abnormality.
Translocations occur when a portion of two different chromosomes, for example chromosomes number 13 and 21, have “swapped” positions with each other. The result (from our example) is that a little piece of chromosome 13 is now on chromosome 21 and a little piece of 21 is now on chromosome 13.
This can occur in the chromosomes of the egg or the sperm.
When fertilization occurs in these couples, a few different possible outcomes may occur:
- The embryo may be completely normal
- The embryo may end up with a balanced amount of chromosome material and end up like the parent, essentially, a carrier of the problem
- The embryo may end up with an unbalanced amount of chromosomal material. These embryos, like the aneuploidies will be miscarried.
These abnormalities can be detected with a fetal karyotype analysis unless the amount of swapped information is very small. These micro translocations (also called telomeric translocations) will be missed by standard karyotype techniques. It is therefore important for couples who have recurrent miscarriage to undergo a high resolution chromosome analysis to look for very subtle abnormalities.
Genetic mutations
Maintenance of pregnancy is an extremely complicated process. It is is likely that hundreds of different genes are involved – each one to a small extent. Because of this complexity, it has been difficult to isolate individual genes or gene mutations that are responsible for miscarriage.
Recently, researchers using new bioinformatics techniques, have identified a gene responsible for recurrent miscarriage called FOXD1. They were able to show that women who had certain variants in this gene were ten times more likely to suffer from recurrent miscarriage than those without the variants. FOXD1 acts as a sort of master controller for other genes that are involved in creating the blood vessels necessary to “feed” the placenta oxygen and nutrients and for fine tuning the balance between a mother’s immune system and the placenta. FOXD1 is now referred to as the miscarriage gene.
Testing for FOXD1 is a blood test. There are some ideas for possible treatment but no studies which show benefit yet.
Treatment of recurrent miscarriage due to translocations
As in the case of embryos with aneuploidies, embryos with unbalanced translocations cannot be fixed. They can be prevented if the affected parent’s gametes (sperm or eggs) are not used. This is an indication for egg donation or sperm donation.
Preimplantation genetic diagnosis can also be used to identify embryos with translocation abnormalities during an in vitro Fertilization cycle assuming that the translocation is known ahead of time.
Thrombophilias
Women can have disorders that make it more like to have problems with blood clotting. Blood clotting can be an important cause of miscarriage since the growth and development of the embryo is highly dependent on obtaining oxygen and nutrients from the mother’s blood supply.
Some of the more common causes for increased blood clotting risk are genetic mutations that a woman is born with. For several years now, we have been performing testing for the presence of these mutations:
- Factor 5 Leiden Mutation
- Factor 2 (Prothrombin) Mutation
- Variants in the Methyl tetra hydrofolate reductase (MTHFR) gene
Thrombophilias can also result from deficiency or excess amounts of the factors in the blood that control the balance between bleeding and clotting. These include:
- Protein C Deficiency
- Protein S Deficiency
- Antithrombin III Deficiency
- Hyperhomocysteinemia
- Folate Deficiency
- Plasminogen activator inhibitor
Treatment of miscarriage caused by thrombophilias
In some cases, treatment for these problems entails the use of anti-coagulant medications, that is, medications that lower the risk of blood clotting. Unfortunately, there still isn’t a lot of data about the best way to give the medications so you end up with a fair amount of variability from physician to physician. For example, should the medication be started before pregnancy or only after a pregnancy has been diagnosed? How long should the treatment continue? what is the ideal dose? Until further studies are performed, we can only guess as to the correct answers.
Some problems, like hyperhomocysteinemia, may be treated with high dose supplementation of a B vitamin called folic acid. This technique has proven to be successful with other problems caused by hyperhomocysteinemia.
Immune Causes of miscarriage
Problems with a woman’s immune system make up a much smaller proportion of the causes of miscarriage. There are several types of problems:
- Auto-immunity
- Allo-immunity
- Non-specific
Autoimmune causes of miscarriage
Normally a person’s immune system functions to “fight off” foreign invaders like bacteria and viruses and rid the body of abnormal cells such as cancer. Occasionally, however, the immune system may malfunction causing it to attack and destroy a persons own normal body tissues or cells. In medicine, there are many examples of diseases causes by this autoimmunity: Rheumatoid arthritis, Lupus, and asthma are just a few examples.
Evidence for autoimmunity has been detected as a possible cause of miscarriage. Overall immune problems as a cause for miscarriage are infrequent but autoimmunity makes up the largest proportion of immune mediated miscarriages. Tests performed to detect an autoimmune problem are blood tests that look at the levels of various antibodies. These antibodies are present in all individuals. They are though to represent a problem is the levels are significantly higher than that seen in the general population. It is not known whether these antibodies are directly involved with the loss of the pregnancy or whether they are just a marker for a woman who has an “autoimmune problem”.
Anti-phospholipid antibodies
The most common type of autoantibodies thought to be involved with miscarriage are known as Anti-phospholipid antibodies:
- Anti-cardiolipin antibodies – There are three subclasses: IgG, IgA and IgM. Unfortunately, many of the “abnormal” results that we get can be falsely positive. For example, the IgG subclass is elevated in 6.5% of general population and in 10.6% of women with completely normal pregnancies. The IgM subclass is elevated in 9.4% of the general population and 17% of women with completely normal pregnancies. To further complicate matters, the levels of these antibodies can fluctuate and so it is recommended that a positive test be repeated in six weeks to determine if the elevated antibody levels are persistent.
- Lupus anticoagulants – These are a group of antibodies that are commonly identified in individuals with the disease Lupus. Many women can have evidence for the presence of lupus anticoagulants without actually having the full blown disease. Accurate measurement of this group of antibodies is difficult since there is no direct test. Typically, a woman first has a screening test. The test is based on the fact that when lupus anticoagulants are present, a standard test to look at blood clotting activity called aPTT (activated partial thromboplastin time) becomes abnormal. However, this screening test alone is inadequate to establish the presence of a lupus anticoagulant because many affected patients, especially pregnant women, have normal aPTT’s and sometimes women with an abnormal test have a different type of problem. Thus, additional tests are needed both to establish and exclude the presence of a lupus anticoagulant. Other tests that aid in the recognition and confirmation of lupus anticoagulants include tests for the dilute Russell viper venom time (dRVVT, the hexagonal lipid neutralization test, and testing for alpha-2 glycoprotein I.
Treatment of miscarriages caused by anti-phospholipid antibodies: Anticoagulation
As in the case with thrombophilias, women with recurrent miscarriage and evidence for anti phospholipid antibodies are treated with anticoagulant medications such as Lovenox and baby aspirin. There are two theories as to why this might work.
There is some evidence that anti phospholipid antibodies increase blood clotting risk. Anticoagulants decrease blood clotting risk. Other data point to the possibility that anti-phospholipid antibodies actually interfere with the cells of the developing placenta known as trophoblastic cells. Medications like Lovenox may prevent the antibodies from interfering.
Anti-Thyroid Antibodies
Another type of autoantibody that may be a cause for miscarriage are antibodies which attack the thyroid gland. These are known as anti-thyroid antibodies. Little is known about this class of antibodies. Several studies have suggested that elevated levels are associated with a higher risk of miscarriage. Treatment with thyroid hormone (Synthroid) has been suggested as a way to reduce the risk.
Alloimmune causes of miscarriage
It was once thought that some causes of miscarriage could be explained by immunologic “rejection” of the fetus as an allograft. An allograft is when an organ or tissue is transplanted from one individual to another of the same species. If you think about it, an embryo is part allograft since it contains material (called antigens) that comes from the father and is thus foreign to the mother. It is thought that the mother must have the ability to suppress her immune system so it will not automatically reject this “transplant” as foreign. This is called immune tolerance. If the mother fails to achieve immune tolerance then the fetus will be rejected (aborted). It was thought that immune tolerance was brought about by the mother first recognizing the foreign father’s antigens, then producing “blocking antibodies” which would “coat” the fetal cells and protect them from damage from the mother’s immune “killer” cells.
Treatment of miscarriages due to Alloimmune factors: Paternal Leukocyte Immunization
In the past, a few researchers thought that injecting white blood cells from the father would make it easier for the mother to produce blocking antibodies and reduce the risk of miscarriage. This treatment became known as Paternal Leukocyte Immunization. Unfortunately, we now know that this treatment does not work and in some cases, actually increases the risk for miscarriage. Because it was ineffective and due to safety concerns, in the United States, this therapy was halted by the Food and Drug Administration.
Nonspecific immune causes of miscarriage
In addition to antibodies, the immune system is composed of more than 30 types of white blood cells. A few of these cells have been studied to determine their role in causing miscarriage. They include T lymphocytes and natural killer (NK) cells. The cells can be differentiated by the presence or absence of specific markers on the surface of the cells. These markers are written as abbreviations followed by a (+) or (-) to indicate their presence or absence.
For example, there is a special class of Natural killer (NK) cells (CD3-, CD16-, CD56+).
Natural killer (NK) cells are the main type of lymphocyte in the uterine lining at the time of implantation and during early pregnancy. Uterine NK cells are different from those circulating in peripheral blood. The function of uterine NK cells in pregnancy is still largely unknown. Tests to measure NK cells in the blood may not give useful information on uterine NK cells. Use of powerful therapies to reduce levels of NK cells in women with infertility or recurrent miscarriage is unjustified and is associated with known side effects to mother and fetus.
Uterine abnormalities and miscarriage
A woman can be born with or develop abnormalities of her uterus. Some of these abnormalities have been strongly associated with an increased risk of miscarriage. Others have only weak evidence associating them with miscarriage.
Congenital abnormalities (problems a woman is born with):
- Uterine septum
- Bicornuate uterus
- Unicornuate uterus
- Uterus didelphus
- Various combinations of the above
- Intrauterine adhesions (Asherman’s syndrome)
- Uterine fibroids
- Uterine polyps
- Uterine infections
Treatment of miscarriages due to uterine abnormalities
Treatment of uterine abnormalities is usually surgical. When possible, hysteroscopy is used. Hysteroscopy is the passage of a fiberoptic telescope into the uterine cavity. Through operative channels in the telescope, instruments can be introduced to allow the surgeon to cut, vaporize or remove abnormalities.
In some cases, however, surgical repair must be performed through an open surgery going through the abdominal wall.
Progesterone deficiency and miscarriage
After ovulation, the ovaries produce large amounts of the hormone progesterone. Progesterone has an important role. It prepares the uterine lining for implantation of the embryo and maintains the uterine lining afterward. In experiments in primates, if the ovaries are removed soon after the establishment of a pregnancy, it will lead to miscarriage. This forms the basis of the presumption that progesterone production by the ovaries is important for the maintenance of the pregnancy and prevention of miscarriage.
Progesterone levels are difficult to measure accurately, however. There have never been any studies that have been able to accurately correlate progesterone levels with miscarriage risk. Most physicians believe that progesterone supplementation is low in risk so it is often given to women as a treatment to prevent miscarriage. In reality, it may be of limited benefit.
Environmental causes of miscarriage
Several factors have been associated with an increased risk of miscarriage. Tobacco, alcohol and caffeine use by a woman or even her partner increase miscarriage risk. Several herbal remedies can also trigger an abortion. Mercury in the diet, mostly from certain types of seafood, have been associated with miscarriage and birth defects. Even chlorine compounds in the drinking water are thought to play a role.
Signs and Symptoms of Miscarriage
The symptoms of miscarriage can vary widely. In some cases, a pregnancy can be lost so early that a woman was not even aware she was pregnant. In other cases, the only sign of miscarriage may be that a woman’s period came a few days later than normal. On the other side of the spectrum the symptoms of miscarriage can be quite obvious or severe.
Early Miscarriage Signs and Symptoms
The most common finding in women who have had a very early miscarriage is having no symptoms at all. Various signs and symptoms might include one or more of the following:
Menstrual cycle abnormalities
- Late period
- Heavier than normal period
- A period that lasts more days than usual
Testing abnormalities
- A home test was positive but has now turned negative
- A serum pregnancy test was positive but has now turned negative
- A serum pregnancy test measuring hCG levels was previously increasing but has now started dropping
Other physical sensations
- Loss of breast tenderness
- Loss of nausea
- Subjective feeling of "not being pregnant"
Later Miscarriage Signs and Symptoms
The further a pregnancy has progressed the more likely it is that a woman may experience signs and symptoms that are commonly associated with miscarriage.
Abnormal bleeding
- Dark brown spotting
- Light pink spotting
- Bright red spotting
- Bright red bleeding
- Passing blood clots – many women who aren’t used to seeing blood clots normally during their menstrual flow may think that they are passing pregnancy tissue. While this is true occasionally, it is far more common to pass clots alone.
Physical symptoms
- Lower pelvic cramping
- Severe pelvic cramping
- Generalized or diffuse pelvic pain
Note: Pain in a pregnant patient may also be a symptom of a more serious problem such as an ectopic pregnancy or a ruptured ovarian cyst. Any severe pain or pain that is localized to one side or the other should be thoroughly investigated.
Testing abnormalities
- A serum pregnancy test measuring hCG levels was previously increasing but has now started dropping
- Ultrasound reveals a fetus without a heartbeat
- Two Ultrasounds a week apart have failed to show any change
- An ultrasound previously showed a pregnancy in the uterus but it is no longer visible
Note: At this point a lost pregnancy may still result in a positive home test or blood test. A quantitative level is needed to show the numbers are decreasing.
Other physical sensations
- Loss of breast tenderness
- Loss of nausea
- Subjective feeling of "not being pregnant"
Natural Killer in Miscarriage and Infertility
There has been much interest in the possible role of the immune system in determining the outcome of fertility treatment and pregnancy. Unfortunately, there has been much misinformation about the role of natural killer cells in miscarriage and infertility. Natural killer cells, also known as NK cells or CD56 cells, have been perhaps misnamed and this contributes to the confusion surrounding them. Natural killer cells are a diverse group of cells that can be found in the blood and other areas of the body including the uterus. They earned the name “killer” cells because it was found that the type of natural killer cells found to circulate in the blood were able to bind to and kill certain cancer cells and virus infected cells. However, other types of NK cells lack this ability or only to a much lesser extent.
Blood tests for Natural Killer Cells are not helpful
Based on the assumed similarities between NK cells in blood and uterine NK cells, it has become increasingly common for fertility doctors to recommend blood tests for Natural Killer cells in women with infertility and recurrent miscarriage. These recommendations are based on the unproven assumption that women with recurrent miscarriage and infertility have abnormalities in the function of their uterine NK cells and that the measurement of NK cells in the blood can somehow identify those women who suffer from a malfunction of their uterine NK cells.
Both of these assumptions appear to be wrong.
First, measurement of the number of percentage of Natural Killer Cells in the blood do not reflect the number in the uterus. The percentage of NK cells in blood can be affected by many factors including sex, ethnicity, stress, and age, but there is no indication that elevated concentrations are ever harmful. On the other hand, uterine NK cells will see their numbers change based on a woman’s hormone production during her menstrual cycle. The levels are low before ovulation and increase dramatically, day by day, after ovulation.
Second, blood NK cells are quite different from uterine NK cells. They look different under a microscope, the react differently and they function differently. For example, uterine NK cells have very weak activity in killing cancer cells. Recently, studies of large groups of women have failed to find any relationship between the levels of NK cells in the blood and either infertility or miscarriage.
These incorrect assumptions have led doctors to recommend ineffective and sometimes dangerous therapies to women to suppress their NK cells such as prednisolone, intravenous Ig (IVIG), intralipid, and TNF-α–blocking agent. This is based on a idea that there is a correlation between excessive number or activity of NK cells and adverse reproductive outcome. As noted above, high quality studies have not found this to be true.
What do uterine NK cells do?
The function of uterine NK cells is not completely understood. Studying the function of uterine NK cells is complex and difficult. The best evidence currently points to uterine NK cells being an important mediator between the placenta and the uterus. To understand this role, it is important to understand some basics about the placenta, the uterus and how the two interact with each other.
The placenta comes from the fetus – not the mother. It is composed of cells called trophoblast cells which literally invade into the mother’s uterine lining. In the mother’s uterus, there are blood vessels called spiral arteries. In order for a pregnancy to be successful, the trophoblast cells must come close to the mother’s spiral arteries and then cause changes in the arteries to ensure that they receive a good blood supply. This is called arterial remodeling. The likely function of uterine NK cells is to “cooperate” with trophoblast cells to guarantee correct arterial remodeling ensuring the supply line to the growing fetus. The uterine NK cells must recognize that fetal cells are present in the uterus and they must be activated to produce the molecules necessary for correct spiral artery remodeling.
Should you undergo treatment for elevated or abnormal NK cells?
Use of the treatments noted above (prednisolone, intravenous Ig (IVIG), intralipid, and TNF-α–blocking agent) is an attempt to suppress the number of uterine NK cells. This is based on a misunderstanding of the basic science. It is not inhibition of uterine NK cells that is needed, but rather the right degree of activation that is of importance. These treatment therefore could potentially have serious adverse side effects. Incorrect or insufficient remodeling of the spiral arteries can lead to complications of pregnancy such as pre-eclampsia, fetal growth restriction and stillbirth.
Conclusions
- Blood tests for natural killer cells are not an indicator of uterine natural killer cell numbers or function and do not predict miscarriage or infertility.
- Tests to determine levels or “activity”of uterine natural killer cells are of no benefit either since the exact way that natural killer cells work is not known.
- Treatments to suppress natural killer cells lack any scientific validity and are potentially harmful.
Sitagliptin (Januvia) Treatment for Recurrent Miscarriage
Recent evidence has pointed to the possibility that some miscarriages may be due to defects in the function of the uterine lining. Women with recurrent miscarriage, especially those that have had a miscarriage of a chromosomally normal embryo, have been found to have low levels of a type of stem cell – endometrial mesenchymal stem-like progenitor cells (eMSC) in the basal (bottom) layer of the endometrium (uterine lining). They also appear to have problems converting the cells in the uterine lining (endometrial stromal cells – EnSC) into a form that will support pregnancy (decidual cells – DC ) and away from a type that may cause miscarriage (senescent decidual cells – SASP). Treatments that increase the eMSC and restore a healthy ratio of decidual cells may reduce the risk for miscarriage.
What is sitagliptin?
Sitagliptin, also known as Januvia, belongs to a class of medications called DPP-4 inhibitors. DPP-4 is an enzyme that breaks down certain proteins. One of the proteins that DPP-4 breaks down is called incretin. This prolongs the action of incretin in the body which helps control blood sugar. Thus, the primary use currently for sitagliptin is to treat people with Type 2 diabetes. Sitagliptin is FDA approved in the United States as a treatment for Type 2 diabetes.
How does sitagliptin help the uterus?
Another protein that is broken down by DPP-4 is called SDF-1. By blocking the action of DPP-4, sitagliptin can prolong the action of SDF-1. SDF-1 is produced in the uterine lining. When an follicle / egg is maturing in the ovary, the follicle produces estrogen. Estrogen makes the uterine lining thicker but it also increases the amount of SDF-1 that is produced by the endometrium. SDF-1 circulates in the blood and reaches the bone marrow. As a result, the bone marrow produces a type of stem cell called BMDC (Bone Marrow Derived Cells). The BMDCs lodge in the basal layer of the endometrium and are converted into eMSCs which help with regeneration of the uterine lining.
How does sitagliptin reduce the chance for miscarriage?
It is thought that sitagliptin improves the health of the uterine lining by increasing the eMSCs which are low in some women with recurrent miscarriage, and convert more endometrial stromal cells into healthy decidual cells instead of unhealthy senescent cells. The embryo may therefore have a better chance for survival after implantation.
Is there any evidence that sitagliptin reduces the risk for miscarriage?
Yes. This year (2020), scientists in England recruited a number of women aged 18 to 42 with a history of 3 or more miscarriages. Half the group received sitagliptin and half received a placebo (phony, inactive capsules). Subjects receive this treatment for three months. Neither the doctors nor the patients knew who got the real pills. This is known as a double-blind, randomized, placebo-controlled trial. This is considered this highest quality type of medical study because it reduces the chance for other variable to affect the results.
The researchers found that the women who received sitaglitpin: 1) Increased the number of eMSCs in their endometrium 2) Increased the number of decidual cells compared to senescent cells and 3) were more likely to have live births.
Specifically, in the group who received and completed treatment with sitagliptin, there were 8 live births out of 17, one termination of pregnancy at 16 weeks for a fetal abnormality and 3 spontaneous pregnancy losses before 12 weeks of gestation. A chromosome analysis was performed in 2 of 3 miscarriage cases and both showed a chromosome abnormality.
In the placebo group, there were 7 live births and 6 spontaneous pregnancy losses before 12 weeks out of 19 patients. Chromosome analysis was performed in only one of the losses. The results was normal. No chromosome abnormality.
Conclusion
Sitagliptin appears to be a novel way to improve the uterine lining prior to implantation by recruiting more bone marrow cells to help with endometrial regeneration. Treatment was well tolerated. although the group was very small, there appeared to be a greater chance for a live birth.
If you are interested in trying sitagliptin therapy, register to become a patient now.
Listeria pregnancy and miscarriage
In 2008, the United States Department of Agricultural stepped up a media education campaign regarding food safety in general and infection with Listeria in particular. They stressed that pregnant women are at high risk for getting sick from Listeria and that listeriosis (Listeria infection) can cause miscarriage and other complications of pregnancy.
What is Listeria?
Listeria is a type of bacteria found everywhere – in soil and ground water and on plants. Women can carry Listeria in their bodies without becoming sick. Most infections in women result from eating contaminated foods. Most people are not at increased risk for listeriosis. Hormonal changes during pregnancy have an effect on the mother’s immune system that lead to an increased susceptibility to listeriosis in a pregnant woman. In fact, Listeria infection is about 20 times more common in pregnant women than in the general population. Pregnant women account for 27% of all listerial infections.
Listeria symptoms in pregnant women
Because the symptoms of listeriosis can take a few days or even weeks to appear and can be mild, you may not even know you have it. In pregnant women, listeriosis may cause flu-like symptoms with the sudden onset of fever, chills, muscle aches, and sometimes diarrhea or upset stomach. The severity of the symptoms may vary. If the infection spreads to the nervous system, the symptoms may include headache, stiff neck, confusion, loss of balance, or convulsions. A blood culture can be performed to find out if your symptoms are caused by listeriosis.
Listeria can cross the placenta and affect a fetus.
Listeriosis and miscarriage
I reviewed the medical literature and found there is actually very little data linking listeriosis to miscarriage in human beings. Most of the research on the effects of Listeria in pregnancy that is available mostly involves problems later in the 2nd or third trimester or the study reported on a few isolated cases. In 1991, the only large scale study of women with recurrent early miscarriage was conducted.
Uterine tissue and swabs from the cervix were obtained and tested for the presence of Listeria. During the 10-year study period, none of the patients with recurrent miscarriage were found to have the bacteria. The study authors concluded that Listeria may contribute to miscarriage, but probably not on a recurrent basis. Routine testing for Listeria in an asymptomatic woman in a clinical setting is not cost-effective and is therefore unwarranted. They also concluded that it is unwarranted to give routine administration of antibiotics to treat Listeria to women who have had a history of recurrent miscarriage.
That being said, it is not unreasonable for a pregnant woman to follow the safety measures for reducing the chance of becoming sick with a food borne illness.
- Do not eat hot dogs, luncheon meats like bologna, or deli meats unless they are reheated until steaming hot.
- Do not eat soft cheeses such as feta, Brie, Camembert, blue-veined cheeses, and Mexican-style cheeses such as “queso blanco fresco” unless it is labeled as made with pasteurized milk. Make sure the label says “Made with Pasteurized Milk”.
- Hard cheeses, semi-soft cheeses such as mozzarella, pasteurized processed cheese slices and spreads, cream cheese, and cottage cheese can be safely consumed.
- Do not eat refrigerated pâté or meat spreads. Canned or shelf-stable pâté and meat spreads can be eaten.
- Do not eat smoked seafood found in the refrigerated section of the store unless it is an ingredient in a cooked dish such as a casserole.
Examples of refrigerated smoked seafood include salmon, trout, whitefish, cod, tuna, and mackerel which are most often labeled as ‘nova-style,” “lox”, “kippered”, “smoked”, or “jerky”. This fish is found in the refrigerated section or sold at deli counters of grocery stores and delicatessens. Canned fish such as salmon and tuna or shelf-stable smoked seafood may be safely eaten.
- Do not drink raw (unpasteurized) milk or eat foods that contain unpasteurized milk.
- Use all perishable items that are precooked or ready-to-eat as soon as possible.
- Clean your refrigerator regularly using hot water and soap.
- Clean up all spills in your refrigerator right away – especially juices from hot dog packages or raw meat or chicken or turkey.
- Use a refrigerator thermometer to make sure that the refrigerator always stays at 40º F or below and a freezer temperature of 0º F or below.
- Wash your hands after you touch hot dogs, raw meat, chicken, turkey or seafood or their juices.
According to the CDC website, “if you have eaten a contaminated product and do not have any symptoms, most experts believe you don’t need any tests or treatment, even if you are pregnant. However, you should inform your physician or healthcare provider if you are pregnant and have eaten the contaminated product, and within 2 months experience flu-like symptoms.”
PGT for miscarriage
Preimplantation Genetic Testing (PGT) is a method used to identify genetic and chromosomal abnormalities in embryos. There are many potential applications for PGD / PGT in the field of reproductive medicine. One of the most exciting uses for PGD / PGT is the ability to decrease the rate of miscarriage.
Miscarriage due to chromosome abnormalities
The vast majority of miscarriages are due to abnormalities in the number of chromosomes contained in the embryo. Many of these are currently detectable by PGT. The biologic process by which embryos receive their chromosomes is complex. Prior to ovulation, an egg has two extra sets of chromosomes. At the time of ovulation, one set of chromosomes is pushed out of the egg into a tiny cell called the first polar body. In an IVF cycle, this occurs when a woman takes the hCG trigger injection. At the time of fertilization, the second extra set of chromosomes is pushed out into the second polar body. This second extra set of chromosomes is essentially replaced by the chromosomes contained in the sperm. When fertilization is completed, therefore, the egg should have contributed one set of 23 chromosomes and the sperm should have contributed one set of 23 chromosomes. Thus, an embryo that contains 23 pairs of chromosomes, for a total of 46, is considered normal or euploid.
Unfortunately, during this complicated process, occasionally an embryo will lose or gain one or more chromosomes. These embryos are abnormal and are called aneuploid. Certain chromosomes seem to be more prone to gain or loss. So for example, embryos with extra copies of chromosomes 13, 18 or 21 occur much more commonly than embryos with extra chromosomes 1, 2 or 3.
If an embryo contains an extra or missing chromosome in all of its cells, there are only three possible outcomes for that embryo. Most of these aneuploid, abnormal embryos will never implant into the uterus and produce a pregnancy. If the abnormal embryo does implant, the majority will be lost during the early portion of the pregnancy. This is the most common cause of miscarriage in human beings. If an abnormal embryo does not miscarry, the baby born will have birth defects. One of the most well known birth defects is when an extra copy of chromosome 21 is contained in the embryo. These babies are born with a disorder called Down’s syndrome.
As women age, the percentage of embryos with chromosomal abnormalities increases. This is the primary reason why older women have lower fertility rates, higher miscarriage rates and higher rates of birth defects.
Currently, there is no known method to prevent embryos from developing these chromosome abnormalities. PGD / PGT can be used, however, to detect embryos with these abnormalities before they are placed into the uterus.
Preimplantation Genetic Testing
The PGT method most commonly used to detect the number of chromosomes in an embryo is called Next Generation Sequencing (NGS). This is a rapid and highly efficient technique for accurately determining the number of chromosomes.
PGT for miscarriage
The couples who are at highest risk for chromosome abnormalities and miscarriages include those in whom the female is older. In fact, the older the female, the higher the rate of abnormalities found and the higher the miscarriage rate. Others at high risk include couples who have had recurrent miscarriage.
PGT for recurrent miscarriage
In 4-5% of couples with recurrent miscarriage, either the male or female has a structural abnormality involving two of their chromosomes known as a translocation. A translocation involves breakage of two chromosomes with the pieces going to the other chromosome. For example, a 13:21 translocation means that a small bit of chromosome 13 is attached to chromosome 21 and a small piece of chromosome 21 is attached to chromosome 13. The individual who carries a translocation may be completely unaffected because the total amount of DNA is normal. This is called a balanced translocation.
However, if a translocation carrier tries to reproduce, the embryos produced may have too much or too little DNA. This is called an unbalanced translocation and will lead to miscarriage.
PGT can be used to detect translocations in embryos.
In studies of couples with recurrent miscarriage that have a translocation, the risk of miscarriage was reduced by over 90%.
