Beta-cell function and visceral fat in lactating women with a history of gestational diabetes.

Lactation has been recommended as beneficial for the maternal metabolic abnormalities associated with glucose intolerance and diabetes risk, although associations between breastfeeding (BF), glucose tolerance, and adipose tissue distribution are unknown. Therefore, a population of women with recent gestational diabetes (GDM) was evaluated with comparison of results for lactating versus nonlactating women. A total of 26 women participated (14 BF and 12 nonbreastfeeding [nonBF]) with a singleton vaginal delivery after 36 weeks gestation. At 3 months postpartum, each woman completed a 75-g oral glucose tolerance test (OGTT), a frequently sampled intravenous glucose tolerance test (FSIGT), and computed tomography (CT) scanning for adipose distribution and mass. Insulin sensitivity was not significantly different between BF and nonBF groups (4.97 +/- 0.78 v 3.44 +/- 1.0 x 10(-4) min(-1)/(microU/mL) nor was glucose effectiveness (1.92 +/- 0.22 v 1.56 +/- 0.19 x 10(-2) min(-1)). However, the disposition index (DI) (insulin sensitivity [S(I)] x acute insulin response to glucose [AIRg]) was higher in the BF group (129.9 +/- 26.0 v 53.4 +/- 18.0 x 10(-4) min(-1); P =.03). Visceral fat (103 +/- 14 v 97 +/- 15 cm(2)) and subcutaneous fat (362 +/- 36 v 460 +/- 68 cm(2)) were similar between the groups. We conclude that 3 months of BF in a population with previous GDM was associated with improved pancreatic beta-cell function, but not with any difference in measures of adiposity.