Do birth control pills cause birth defects if taken during early pregnancy?
Answers from Roger W. Harms, M.D.
Taking birth control pills during early pregnancy isn't thought to increase the risk of birth defects.
A 2009 study suggested an association between the use of birth control pills during the time of conception and an increased risk of low birth weight or preterm delivery. Also, older research suggested that use of certain birth control pills during pregnancy could pose a risk of developmental problems with a female baby's sexual organs — such as enlargement of the clitoris. Generally, however, these concerns haven't been observed in clinical experience.
It might be difficult to recognize the signs and symptoms of pregnancy if you become pregnant while taking the minipill (progestin-only birth control pill) because nausea, breast tenderness and irregular menstrual bleeding — common signs and symptoms of pregnancy — are also possible side effects of the minipill. In addition, if you do conceive while taking the minipill there's a slightly higher chance that the pregnancy will be ectopic — when the fertilized egg implants outside the uterus, usually in a fallopian tube.
As a precaution, stop taking birth control pills if you suspect you're pregnant. Until the pregnancy is confirmed or ruled out, use another method of birth control — such as condoms. If you're concerned because you took birth control pills before you knew you were pregnant, be assured that there's little risk. It's always important to discuss any medication use during pregnancy with your health care provider, however.
Jul. 28, 2011
See more Expert Answers
- Waller K, et al. Use of oral contraceptives in pregnancy and major structural birth defects in offspring. Epidemiology. 2010;21:232.
- Chen X, et al. Recent oral contraceptive use and adverse birth outcomes. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2009;144:40.
- Oral contraceptives. In: Briggs GG, et al. Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk. 8th ed. Philadelphia, Pa.: Wolters Kluwer Health Lippincott Williams & Wilkins; 2008:1371.
- Ahn AK, et al. Pregnancy outcome after exposure to oral contraceptives during the periconceptional period. Human & Experimental Toxicology. 2008;27:307.
- Raymond EG. Progestin-only pills. In: Hatcher RA, et al. Contraceptive Technology. 19th ed. New York, N.Y.: Ardent Media, Inc.; 2007:181.
- Kaunitz AM. Progestin-only pills (minipills) for contraception. http://www.uptodate.com/index.html. Accessed May 23, 2011.
- Harms RW (expert opinion). Mayo Clinic, Rochester, Minn. May 25, 2011.