Answers to Frequently Asked Questions About...
Safety
Can emergency contraceptive pills cause birth defects?
No, emergency
contraceptive pills ("morning
after pills" or "day after pills") do not appear
to cause any birth defects. Although no reliable studies have looked
specifically at women who gave birth after using emergency
contraception, two strong reasons exist for concluding that emergency
contraceptive pills will not harm a developing fetus.
First, emergency contraceptive pills contain the same hormones as
many daily birth control pills, which a number of studies have found
cause no increased risk of birth defects in children born to women
who continued to take them because they didn’t realize they
were pregnant. As a result, the United States Food and Drug Administration
removed warnings about the possibility that oral contraceptives could
harm a fetus several years ago. Second, even if you don’t realize
you are pregnant, you would take emergency
contraceptive pills long before the organs would start to develop
(a process called “organogenesis”), making it impossible
for emergency contraception
to lead to birth defects.
A thorough and up-to-date academic review of the medical and social
science literature on emergency contraception is available; click
here for the PDF 
.