Is it safe for expecting mothers with diabetes to express breast-milk during late pregnancy?

This study investigated whether or not it was safe for pregnant women with diabetes to express breast-milk before birth. The authors concluded that expressing milk from 36 weeks of pregnancy was safe in patients at low risk of complications.

Babies born to women with diabetes are at an increased risk of hypoglycemia (very low blood sugar) and subsequent admission to neonatal intensive care units (NICUs). Breastfeeding is the recommended feeding method for newborn babies. In the case of patients with diabetes, the colostrum (i.e. the milk produced during pregnancy) can regulate infant blood sugar levels more effectively than infant formula milk. Unfortunately, babies who experience low blood-sugar tend to be separated from their mothers. They are thus less likely to be breastfed when compared to other babies. Many practitioners currently recommend that expecting mothers express milk in the weeks leading up to birth. There is little evidence to date, however, to support this advice. 

This study investigated whether the practice was safe for women with diabetes and their babies. This study included 635 women with pre-existing or gestational diabetes. All were expecting to give birth to only one baby and were between 34 and 37 weeks of pregnancy. The patients were divided into two groups: 319 expressed milk from 36 weeks onwards while the remaining 316 did not. All of these patients were at low risk of complications (i.e. no history of bleeding, caesareans, excess protein in the urine or any suspicion of problems with the fetus). 

Both groups had similar NICU admission rates: 15% of the babies born to women who expressed milk and 14% of the non-expressing group were admitted. There was also no difference in duration of pregnancies between the groups. The babies of the expressing mothers were more likely to be exclusively breastfed during the first 24 hours of life. Mothers did not report increased hypoglycemia while expressing milk.

A small proportion (less than 1%) of infants from both groups experienced adverse effects (such as breathing problems or abnormal brain function). 

This study concluded that in patients at low-risk for complications, there is no increased risk of harm from expressing breast milk in late pregnancy when compared to not expressing.