The return of fertility after birth is not entirely predictable, and conception can occur before the woman resumes her first menstrual period. A woman who is not fully and exclusively breastfeeding is able to become pregnant again as soon as 4 to 6 weeks after childbirth, and she should plan to begin some sort of contraception before starting to have sexual intercourse again. Full and exclusive breastfeeding gives good protection against conception, but cannot be relied on as 100% effective. A breastfeeding woman is usually protected from pregnancy only if:
- She is no more than 6 months postpartum
- She is breastfeeding exclusively (8 or more times a day, including at least once at night; no daytime feedings more than 4 hours apart and no night feedings more than 6 hours apart; no complementary foods or fluids given to the baby)
- Her menstrual cycle has not returned.
Numerous safe methods of contraception are available for the breastfeeding woman.