Many people think that one of the many advantages to breastfeeding is that it is a great source of contraception. In fact, women can get pregnant while they're exclusively breastfeeding, it does happen. Then the question becomes for a lot of moms, "If I am pregnant, can I continue to breastfeed or do I need to ween?" What happens often is that if you are pregnant, your milk supply will go down, and sometimes significantly. If the baby is under a year, often the mother can continue to breastfeed but she needs to supplement with formula because the baby's not getting enough to eat. If the baby's over a year and eating other foods, often mothers can continue to breastfeed without using formula. One challenge is the nipples tend to be really tender when women are pregnant and if you put a nursing toddler on top of those nipples, it can be quite a challenge. Some physicians are concerned that breastfeeding while pregnant may increase the risk of miscarriage, so that's something a mother would need to discuss with her doctor to see if she's a good candidate to continue nursing while she's pregnant.