Approximately one-third of reproductive aged women still believe that taking oral contraceptives cause infertility or difficulty in achieving pregnancy after the pills are stopped. This is despite the fact that several studies in recent years have shown no effect of birth control pills on fertility. Another study looking at the impact of birth control pills on fertility was recently presented at the 55th annual clinical meeting of the American College of Obstetricians and Gynecologists (ACOG). Dr. Maureen Cronin and colleagues followed women who discontinued birth control pills in order to become pregnant. The primary endpoint of the study was the time it took for these women to conceive. They also evaluated other factors such as age of the women attempting pregnancy, the type of hormones contained in the birth control pills used, and the length of time women took birth control pills before attempting pregnancy. The group of women studied was already participating in a European study of birth control pills. The European study had enrolled about 60,000 new birth control pill users. During the study, 2064 (3.5%) of these women decided to stop birth control pills in order to become pregnant. These women were then studied for at least 2 years.

Birth control pills do not cause infertility

The results of the study were very reassuring. 21% of the women became pregnant within the first month after stopping birth control pills. The normal fertility rate in women for a single month is 20-25%. One half of the women were pregnant by three months. One year after they had discontinued birth control pills, about 80% of the women were pregnant, which also is similar to pregnancy rates among women who had never taken birth control pills.

Long term birth control pill use does not cause infertility

The study also refuted another widely held belief: that conception becomes harder the longer a woman is on birth control pills. Of those women who had taken birth control pills for two years or less, 79.3% had become pregnant within 1 year of stopping compared with 81% of women who had used birth control pills for more than 2 years. There was also no difference in the pregnancy rates based on the type of progesterone contained in the birth control pills. All birth control pills contain the same type of estrogen. No adverse effect was identified when comparing women under or over age 35. Although older women conceived less frequently than younger women, their results were similar to those seen in women who had never taken birth control pills.

Conclusion

One of the factors that tends to foster the belief that birth control pills cause infertility is when the regularity of women's menstrual cycles changes. While on birth control pills, women will have very regular periods regardless of any problems that may exist in their underlying reproductive system. When women stop birth control pills and those underlying problems then manifest themselves, their periods may become irregular. The birth control pills are blamed for causing the underlying problems instead of the more likely scenario which is that the birth control pills were merely covering up the problem. The results of this study indicate that use of birth control pills do not affect a woman's ability to achieve pregnancy once the pills are stopped. Longer use of birth control pills does not impart a negative effect. The type of birth control pill taken is also irrelevant. Hopefully, the results of this study will become more widely known by both doctors and patients.