These studies look at the effects of breastfeeding on diabetes in mothers, and the effects of early expression for babies born to diabetic mothers.
Lactation Duration and Progression to Diabetes in Women Across the Childbearing Years
This observational 30-year study found that increasing lactation duration was associated with a strong, graded relative reduction in the incidence of type-2 diabetes even after accounting for pre-pregnancy biochemical measures, clinical and demographic risk factors, gestational diabetes, lifestyle behaviors, and weight gain that prior studies did not address. The graded risk reduction ranged from 25% for 6 months or less to 47% for 6 or more months of lactation.
Advising women with diabetes in pregnancy to express breastmilk in late pregnancy (Diabetes and Antenatal Milk Expressing [DAME]): a multicentre, unblinded, randomised controlled trial
This Australian study examined the safety and efficacy of antenatal expressing in women with diabetes in pregnancy, using the proportion of infants admitted to the neonatal intensive care unit (NICU) as an outcome measure. The researchers found that the proportion of infants admitted to the NICU did not differ between those whose mothers had expressed breastmilk twice per day from 36 weeks’ gestation and those who hadn’t. They concluded that there is no harm in advising women with diabetes in pregnancy at low risk of complications to express breastmilk from 36 weeks’ gestation.
Foster, DA, et al (2017), Advising women with diabetes in pregnancy to express breastmilk in late pregnancy (Diabetes and Antenatal Milk Expressing [DAME]): a multicentre, unblinded, randomised controlled trial. The Lancet, DOI: http://dx.doi.org/10.1016/S0140-6736(17)31373-9
Breastfeeding and reduced maternal risk of diabetes and heart disease
A study of 139,681 women found that women who reported a lifetime history of more than 12 months of lactation were 10-15% less likely to have hypertension, diabetes, hyperlipidemia, and cardiovascular disease than those who had not breastfed.
Lactation intensity and diabetes-related outcomes
A study carried out in the US aimed to examine the association between breastfeeding intensity and maternal blood glucose and insulin and glucose intolerance at 6–9 weeks after a pregnancy with gestational diabetes mellitus (GDM). The authors conclude that higher intensity of lactation was associated with improved fasting glucose and lower insulin levels at 6–9 weeks’ postpartum and argue that lactation may have favourable effects on glucose metabolism and insulin sensitivity that may reduce diabetes risk after GDM pregnancy.
Gunderson EP, Hedderson MM, Chiang V et al (2011) Lactation Intensity and Postpartum Maternal Glucose Tolerance and Insulin Resistance in Women With Recent GDM: The SWIFT cohort. Diabetes Care. Published 19 October 2011, 10.2337/dc11-1409
Reducing risk of maternal type 2 diabetes
A cohort study of 52,731 women examined the effect of childbearing and maternal breastfeeding on a woman’s subsequent risk of developing type 2 diabetes. The authors conclude that compared to nulliparous women, childbearing women who do not breastfeed have about a 50% increased risk of type 2 diabetes in later life. Breastfeeding substantially reduces this excess risk.