Breastfeeding During Pregnancy

Many women who have become pregnant while still breastfeeding find that they want to continue the nursing relationship with their child but have many questions about breastfeeding during pregnancy. Most moms have the same concerns of safety, nutrition and comfort when it comes to breastfeeding during pregnancy.

Will breastfeeding during pregnancy cause pre-term labor?
The stimulation of the nipples causes the release of a hormone called oxytocin. After childbirth, breastfeeding helps to the uterus to return to a normal size because of the contractions caused by oxytocin. Oxytocin is also important in labor because it causes contractions.

However, in the normal, healthy pregnancy there is little need for concern about breastfeeding causing contractions. The reason for this is the “oxytocin receptors sites” on the uterus. These uterine cells detect oxytocin when it is present and respond by causing contractions of the uterus. In a pregnant woman who is less than 38 weeks gestation there are very few of these “oxytocin receptor sites” on the uterus. By 38 weeks, the cells begin to increase gradually. Once a woman is actually in labor, the cells increase 300 times. The uterus is further protected from oxytocin stimulation before term by the absence of “gap junction proteins” which enable the oxytocin receptor sites to respond to oxytocin. The high levels of progesterone during pregnancy also stand in the way of oxytocin causing contractions during pregnancy.

While most women should consider breastfeeding during pregnancy to be a safe act, those women who have experienced preterm labor in previous pregnancies or are at risk for preterm labor in their current pregnancy should not continue breastfeeding during pregnancy. On some occasions women at risk for preterm labor have continued breastfeeding during pregnancy. This is only advisable if permission is given by the obstetrician who knows the history of the pregnancy and any previous pregnancies of the woman.