Breastfeeding has historically been used as a method of birth control, called the lactational amenorrhea method (LAM). But 3 conditions must be met to make sure that it works:

• Baby must younger than 6 months old. After your baby is 6 months old, your period is more likely to come back which means you can become pregnant again.
• You must be exclusively breastfeeding your baby. This means no pumping, pacifiers, formula or other supplements. And you have to breastfeed for both day and night feeding, typically not going more than 4 hours between feedings during the day and no more than 6 hours between feedings at night.
• You must not have a period (amenorrhea). When your periods start, use some other birth control method.

When these conditions are met, LAM has been shown to be about 98% effective. For many who exclusively breastfeed, they will have a light period before ovulating, but it is possible to ovulate and get pregnant before having your first postpartum period.