During pregnancy, a mother’s breasts and nipples can become quite tender, and the volume and content of her milk will change. As breast milk volume decreases, sodium and protein increase, and milk sugars (lactose and glucose) decrease, making the milk look and taste more like colostrum.
Sometimes the breast milk changes cause an older baby or child to lose interest in breastfeeding (child-led weaning). Other times the breast tenderness, common during pregnancy, can make breastfeeding painful, and the mother will decide to wean (mother-led weaning).
Although breastfeeding can cause uterine contractions, there is no evidence that the unborn baby is at risk. However, if you have a history of premature labor or vaginal bleeding during pregnancy, your doctor or midwife may suggest that you wean.
Many women do continue to breastfeed during pregnancy, with little or no difficulty. A toddler who is soon to become an older sibling may take comfort in continuing this ritual, in spite of the changes in the mother's milk.
After your new baby is born, it is possible to breastfeed two babies or a baby and a child at the same time. This is called tandem nursing. To meet the needs of two growing babies, you will need to eat a balanced diet that includes extra calories, drink to satisfy your thirst, and nap when the babies nap. As long as the younger baby is fully breastfed and the older baby is taking some solid foods, you should breastfeed the younger baby first.