Long-term protective effect of lactation on the development of type 2 diabetes in women with recent gestational diabetes mellitus

Abstract

Women with gestational diabetes mellitus (GDM) have a high risk of developing postpartum type 2 diabetes. Strategies to prevent postpartum type 2 diabetes are important to reduce the epidemic of diabetes and its societal impact. Breastfeeding was reported to improve early postpartum glucose tolerance and reduce the subsequent risk of type 2 diabetes. To investigate whether breastfeeding influences short- and long-term postpartum diabetes outcomes, women with GDM (n = 304) participating in the prospective German GDM study were followed from delivery for up to 19 years postpartum for diabetes development. All participants were recruited between 1989 and 1999. Postpartum diabetes developed in 147 women and was dependent on the treatment received during pregnancy (insulin vs. diet), BMI, and presence/absence of islet autoantibodies. Among islet autoantibody-negative women, breastfeeding was associated with median time to diabetes of 12.3 years compared with 2.3 years in women who did not breastfeed. The lowest postpartum diabetes risk was observed in women who breastfed for >3 months. On the basis of these results, we recommend that breastfeeding should be encouraged among these women because it offers a safe and feasible low-cost intervention to reduce the risk of subsequent diabetes in this high-risk population.

FIG. 1.

Cumulative life-table risk of postpartum diabetes in 304 women with GDM who were followed prospectively from delivery. Risk is shown for women who were islet autoantibody-positive (solid black line; n = 32); were islet autoantibody-negative, received insulin therapy during pregnancy, and had a BMI >30 kg/m² (thick black dotted line; n = 39); were islet autoantibody-negative, received insulin therapy during therapy, and had a BMI <30 kg/m² (thin gray dotted line; n = 53); were islet autoantibody-negative, did not receive insulin therapy during therapy, and had a BMI >30 kg/m² (black dashed line; n = 48); and were islet autoantibody-negative, did not receive insulin therapy during therapy, and had a BMI <30 kg/m² (thin gray dashed line; n = 132). Numbers below the graph indicate the number of subjects at each follow-up.

FIG. 2.

Cumulative life-table risk of postpartum diabetes in islet autoantibody-negative women with GDM who breastfed for >3 months (dashed line) compared with those who breastfed for ≤3 months (solid line; P = 0.029) or did not breastfeed (dotted line; P = 0.002). No significant difference was observed between women who breastfed >2 months compared with women who breast-fed ≤3 months (P = 0.2). Numbers below the graph indicate the number of subjects at each follow-up.