Oral contraception in diabetic women. Diabetes control, serum and high density lipoprotein lipids during low-dose progestogen, combined oestrogen/progestogen and non-hormonal contraception

Abstract

Abstract. Thirtyeight women with insulin-dependent diabetes were randomly allocated to contraception with either a progestogen only (Lynestrenol 0.5 mg daily) (LYN), a combined oral contraceptive (OC) (Ethinyl oestradiol 50 μg + Lynestrenol 2.5 mg) (EE + LYN) or a non-hormonal intrauterine device (IUD). Diabetes control (i.e. insulin dosage, blood and urinary glucose and body weight) and the lipid concentration in serum and in high density lipoprotein (HDL) were assessed before and during six months use of the respective contraceptives. In the LYN group urinary glucose excretion increased 10% in spite of unchanged blood glucose, body weight and insulin requirement. All serum lipids decreased; triglycerides by 40% (P < 0.01), cholesterol by 13% (P < 0.01) and phospholipids by 12% (P = 0.06), without alteration of HDL lipids. In the group using combined OC (EE + LYN) the insulin requirement increased by 7% (P < 0.01) without any change in body weight or blood and urinary glucose. Serum as well as HDL lipids remained unchanged. In the IUD group neither diabetes control nor serum or HDL lipids were altered. It is concluded that in insulin-dependent diabetics the progestogen (LYN) has little influence on diabetes control but has a marked, though probably not adverse, effect on lipid metabolism. The combined OC (EE + LYN) may impair glucose homeostasis slightly but has little influence on serum or HDL lipids. These findings seem to differ from those obtained in non-diabetics during administration of contraceptive steroids and these differences suggest that absence of endogenous insulin production enhances the effects of progestogen and reduces the effects of synthetic oestrogens on lipid metabolism.