Breastfeeding could keep you from getting pregnant? This one sure sounds like a hoax, but breastfeeding can help prevent pregnancy under very specific circumstances. It’s a form of birth control known as the lactational amenorrhea method (LAM).
But—and this is a biggie—you do have to follow specific guidelines to ensure you do not accidentally get pregnant while breastfeeding, according to og-gyn Kecia Gaither, MD.
If you nurse your baby at least every four hours (or six during the night), and you feeding your baby only breast milk, your body will naturally stop ovulating. No ovulation means no eggs to fertilize, so you can’t get pregnant. (It also means no period, which is what the “amenorrhea” refers to.) For more details, here’s an overview of how ovulation and menstruation really work.
The LAM method only works for the first six months after your baby’s birth, and it won’t work if:
You feed your baby formula or anything other than breast milk (even if you’re using a combo of each).
You use a breast pump.
You feed your baby solid foods.
If your baby is over six months old, or you are feeding your baby anything other than breast milk, use another form of birth control to prevent pregnancy. Immediately after birth, you should use an estrogen-free method, like the shot, implant, Skyla and Mirena IUDs, or progestin-only pills. Don’t use birth control methods with estrogen, like the Pill, patch, or ring for the first three weeks after delivery.
When used effectively, breastfeeding with the LAM method is about 98 percent effective at preventing pregnancy.