Pregnancy is a kind of metabolic stress test for risk of diabetes later in life; the life time risk of type 2 diabetes mellitus is a whopping seven-fold increase above controls in women with gestational diabetes. Breast feeding has positive metabolic effects and promotes weight loss. It is therefore highly plausible that breastfeeding would reduce the risk of type 2 diabetes in women whose pregnancies were complicated by gestational diabetes. However, there have been surprisingly few studies of this hypothesis, and those that have been done have mostly been retrospective and did not collect enough information to adjust for all known confounders. The small number of prospective studies have been too few to examine for risk-adjusted associations between exposure and outcome. This deficiency in the literature has now been corrected by a mighty study of 1000 women with gestational diabetes, intensively investigated at base line, and followed-up for two years after delivery. The results, after extensive adjustment, are clear. Breastfeeding is associated with a large decrease (approximately 50%) in incidence of diabetes over follow-up, and there is a strong positive association between duration of breastfeeding and degree of protection.
— Richard Lilford, CLAHRC WM Director
- Gunderson EP, Hurston SR, Ning X, et al. Lactation and Progression to Type 2 Diabetes Mellitus After Gestational Diabetes Mellitus. Ann Intern Med. 2015; 163: 889-98.