Parity and type 2 diabetes mellitus: a study of insulin resistance and β-cell function in women with multiple pregnancies

OBJECTIVE: Increasing parity may be a risk factor for the development of type 2 diabetes mellitus and the metabolic alterations during a normal pregnancy induces a prediabetic state; thus, multiple pregnancies may act as a risk factor for development of type 2 diabetes if these physiological alterations in glucose homeostasis are not reversed postpartum. We hypothesize that multiple pregnancies may lead to β-cell exhaustion and that the insulin resistance that occurs during pregnancy may persist after multiple births. RESEARCH DESIGN AND MEASURES: A total of 28 healthy premenopausal women were recruited: 15 high parity women (≥4 children) and 13 body mass index (BMI)-matched and age-matched low parity women (1 and 2 children). The study consisted of an intravenous glucose tolerance test for assessment of β-cell function followed by a hyperinsulinemic euglycemic clamp for assessment of insulin sensitivity. Dual-energy X-ray absorptiometry was performed to assess body composition. RESULTS: All anthropometric measures, measures of body composition and baseline blood samples were comparable between the 2 groups. Neither first phase insulin release (0–10 min, p=0.92) nor second phase insulin release (10–60 min, p=0.62), both measured as area under the curve, differed between the 2 groups. The M-value, calculated as the mean glucose infusion rate during the last 30 min of the clamp period, was 8.66 (7.70 to 9.63) mg/kg/min in the high parity group compared with 8.41 (7.43 to 9.39) mg/kg/min in the low parity group (p=0.69). CONCLUSIONS: We did not detect any effects of increasing parity on insulin sensitivity or β-cell function.