Oral contraceptives and intravenous glucose tolerance. I. Data noted early in treatment.

Abstract

The effect of oral contraceptives (OCs) on intravenous glucose tolerance tests (iv GGT) to see if the results in a "pseudopregnancy state" parallel those of actual pregnancy was evaluated. 65 women (41 nondiabetic; 24 diabetes suspects) took Enovid (5 mg norethynodrel with .075 mg mestranol) for 2-3 months. 12 women (7 nondiabetic; 5 diabetes suspects) took Ovulen (1 mg ethhynodiol diacetate and .1 mg mestranol) and 14 women (7 nondiabetic; 7 diabetes) with intrauterine devices (IUD) served as controls. All subjects had the iv GTT before and after treatment. The GTT was expressed as K, the % fall/min of the blood glucose level from 10-60 min after injection of 25 gm glucose. Enovid caused a significant k decline (p .005) but no change in fasting blood sugar levels. No women in the Ovulen or IUD group had abnormal k values. 6 women with previosly normal k values developed abnormally low values while taking Enovid. 2 of these were in the diabetes suspect group. Diabetes suspects using OCs appeared to show a greater loss in GT than nondiabetic subjects. No correlation was found between carbohydrate metabolism during pregnancy and that of the "pseudopregnancy state" of progestin-estrogen administration. The possible mechanisms responsible for these changes, in particular the role of estrogen, were discussed.