Do birth control pills cause birth defects if taken during early pregnancy?

Answers from Roger W. Harms, M.D.

Taking combination birth control pills or minipills (progestin-only birth control pills) during early pregnancy doesn't appear to increase the risk of birth defects.

While some research has suggested a link between the use of birth control pills near conception and an increased risk of low birth weight, preterm delivery or congenital urinary tract abnormalities, these concerns generally haven't been observed in clinical experience.

However, 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. Keep in mind that it might be difficult to recognize that you're pregnant if you conceive while taking the minipill because nausea, breast tenderness and irregular menstrual bleeding — common signs and symptoms of pregnancy — are also possible side effects of the minipill.

As a precaution, if you suspect you're pregnant take a home pregnancy test. If the home pregnancy test is positive, stop taking the pill. If taking a home pregnancy test isn't possible, stop taking the birth control pill until the pregnancy is confirmed or ruled out. In the meantime, 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, talk to your health care provider, but be assured that there's little risk.

Jul. 24, 2014