Long Lasting Effects of Breastfeeding on Metabolism in Women with Prior Gestational Diabetes

Background & Aims: Breastfeeding improves glucose tolerance in the early postpartum period of women with prior gestational diabetes GDM, but it is unclear whether future risk of metabolic alterations, like type 2 diabetes, is reduced. The aim of this study was to investigate the effect of lactation, three years after pregnancy, on glucose and lipid metabolism in women with prior gestational diabetes. Materials & Methods: A population of women with prior gestational diabetes (Carpenter and Coustan Criteria) was evaluated with comparison of results for “lactating” [BF] versus “nonlactating women” [non BF]. Breast feeding was defined [BF] if lasting? 4 weeks. In each woman a 75-g oral glucose tolerance test (OGTT) was performed to analyze the glucose tolerance, insulin sensitivity/resistance and b-cell function. Fasting serum was used to study their lipid profile (total cholesterol, high-density lipoprotein [HDL] cholesterol, low-density lipoprotein [LDL] cholesterol, and triglycerides), apolipoprotein B, apolipoprotein A1, homocysteine, fibrinogen, hs- CRP, uric acid, microalbuminuria. Statistics: Paired and Un-paired t-test, Mann-Whitney and χ2 tests were used, as appropriate. Results: A total of 81 women were evaluated (62 [BF] and 19 [non BF]). Maternal age (37.1 ± 4.6 vs 37.4 ± 4.9 years), body mass index (26.3 ± 5.6 vs 26.4 ± 5.3 kg/m2), parity (1.9 ± 0.8 vs 1.7 ± 0.8) and length of follow-up (32.2 ± 20.2 vs 32.1 ± 20,0) were not different between the two groups. No effect was visible on glucose tolerance, HOMA-IR and other b-cell function indexes as well as hs-CRP (not significantly lower in non BF), uric acid, total cholesterol, HDL and LDL cholesterol. Levels of significance were only reached for “HOMA-IS” [BF] 1.0 ± 0.7 vs [non BF] 0.6 ± 0.4, p = 0.04) and triglycerides [BF] 83.8 ± 46.7 vs [non BF] 123.2 ± 94.0 mg/dl, p = 0.02). Conclusions: Breastfeeding does not improve the glucose tolerance of our women with prior GDM three years after delivery, even though lower levels of triglycerides and improved insulin sensitivity are still visible.