Washington, DC

-- Pregnant asthmatic women should continue to use their asthma medication in the lowest dose possible to manage symptoms during pregnancy, according to a new Practice Bulletin released today by The American College of Obstetricians and Gynecologists (ACOG). Women with moderate or severe asthma should also be monitored throughout pregnancy for fetal growth restriction and signs of preterm birth.

An estimated 22 million Americans have asthma, a common chronic disease that causes inflammation in the airways and increases sensitivity to allergens and irritants. It affects approximately 4%–8% of pregnancies. Asthma attacks are characterized by wheezing, chest cough, shortness of breath, and chest tightness. During pregnancy, asthma attacks may deprive the fetus of oxygen and have been linked to increased prematurity, growth restriction, other fetal complications, and morbidity and mortality in women. "Previously, there was limited guidance regarding the management of asthma during pregnancy," said Andrew J. Satin, MD, chair of ACOG's Committee on Practice Bulletins-Obstetrics. "With the growing number of asthmatics in the US, it became a priority to formalize recommendations for ob-gyns, who will likely see an increasing number of asthmatic patients," he added. The new recommendations—based on a review of existing studies on asthma and pregnancy—support the findings of the National Asthma Education Prevention Program that state that "it is safer for pregnant women with asthma to be treated with asthma medications than it is for them to have asthma symptoms and exacerbations." "Research consistently shows that women with well-controlled asthma can have healthy pregnancies with excellent maternal and perinatal outcomes," said Mitchell P. Dombrowski, MD, an ACOG Fellow who contributed to the document. "The ultimate goal of controlling asthma during pregnancy is to ensure that the fetus continues to get adequate oxygen by preventing asthma attacks." Because it is unknown how pregnancy will affect an individual woman's symptoms, lung function of women with persistent asthma should be monitored during pregnancy, using common pulmonary function parameters such as spirometry, the peak expiratory flow rate (PEFR), and forced expiratory volume in one second (FEV₁). If possible, first-trimester ultrasound should also be performed to assess fetal growth restriction and risk of preterm birth. Starting at 32 weeks, ultrasound exams to monitor fetal activity and growth should be considered for women with poorly controlled asthma, moderate to severe asthma, or who are recovering from a severe asthma attack. Avoiding allergens and irritants, such as tobacco smoke, that exacerbate asthma can improve maternal well-being and lessen the need for medication. Asthmatic women are advised to identify triggers and do what they can to reduce them at home. Specific measures to reduce mold, dust mite exposure, animal dander, cockroaches, and other environmental triggers may be necessary. If acid reflux stimulates their asthma, women may want to try solutions such as elevating the head of a bed, eating smaller meals, not eating within a few hours of bedtime, and avoiding foods that trigger reflux. Many women with asthma need to use medication to maintain normal respiratory function. Long-term medications—such as inhaled corticosteroids—are used to prevent asthma flare-ups, while rescue therapy‐most commonly inhaled short-acting beta agonists (preferably inhaled albuterol during pregnancy)—provide immediate relief from symptoms. Whatever therapy is used, it should be tailored to supply pregnant patients with the lowest dose necessary to control their asthma. Women who already use immunotherapy (allergy shots) at or near maintenance level to improve asthma symptoms may continue getting shots during pregnancy. However, women should not begin immunotherapy during pregnancy. Allergy shots are typically given with lower doses of serum to start and then are gradually increased to higher levels. These escalating doses may cause anaphylaxis during pregnancy, which has been associated with maternal and fetal death. During labor and delivery, asthma medication should be used. In combination with hydration and adequate analgesia, medication may be enough to keep symptoms under control. Even acute exacerbation of asthma rarely requires cesarean delivery because most women respond to aggressive medical management. Use of asthma medications can continue after delivery and during breastfeeding. Women who are better educated about asthma management and how it relates to pregnancy often have an easier time controlling their symptoms. Pregnant asthmatic patients should be counseled to start rescue therapy at home if they experience symptoms of asthma flare-up, such as coughing, chest tightness, wheezing, shortness of breath, or labored breathing. All women with asthma should be instructed to be attentive to fetal activity. If women notice that their fetus is less active than usual or has stopped moving altogether, they should contact their physician. Practice Bulletin #90, "Asthma in Pregnancy," is published in the February 2008 issue of Obstetrics & Gynecology.