Update on the metabolic effects of steroidal contraceptives

Abstract

Modern oral contraceptive pills are safe and show minimal metabolic effects that have little clinical significance to smoking and reproductive age (even up to menopause). Multiphasic and 30 to 35 micrograms EE fixed combination pills are preferable to higher dose EE pills. Triphasic pills with norgestrel or norethindrone, monophasic norethindrone pills, and combination pills with the newer progestins are all probably metabolically comparable. The levonorgestrel implant is convenient, reversible, and effective and eliminates estrogenic metabolic effects. Metabolic benefits of the pill may include less acne, better preservation of bone mass, and less blood loss. Women who smoke should be encouraged to stop. Women with risk factors for atherosclerosis such as smoking, lipid abnormalities, diabetes, or hypertension should avoid combination pills. Women with a history of pregnancy, steroid-related thrombophlebitis, or thromboembolic disease should not use estrogen-containing pills.

PIP: In the past 30 years mortality from coronary artery disease has decreased in the United States. From 1968 to 1976 it went down from 16.3 deaths among women aged 35-40 to 11.1 deaths/100,000 populations. Among women aged 45-54 the rate decreased from 72.8 to 56.5/100,000. A 1979 study examined the effect of combined oral contraceptives (OCs) on blood lipids in 1500 women using levonorgestrel or LNG pills (150-250 mcg monophasic and 50-75-125 triphasic), norethindrone (.5-1 mg) pills with 30-40 mcg of ethinyl estradiol (EE), and progestin-only preparations. The combination OCs increased triglycerides by 13-75% while progestins did not increase them. Total cholesterol did not change: LDL and HDL II decreased slightly. Another study, the Triphasic Randomized Clinical Trial (TRACT) probe, included 150 women using triphasic OCs: 35 mcg of norethindrone; 30-40-30 mcg of EE, 50-75-125 mcg of norgestrel; or 24 mcg of E, 500-1000-500 mcg of norethindrone. LDL increased from 0 to 11% and HDL II decreased by 29-33% after 6 months of OC use. The rise in HDL and HDL II and fall of LDL was observed in a 1990 study of 150 mcg desogestrel and 30 mcg of EE (Marvelon). OCs with 250 mcg of LNG produced the greatest drop of HDL II. Higher dose OCs used before the 1990s increased glucose levels, plasma insulin levels (especially with norgestrel), and reduced glucose tolerance (particularly by 50 mcg of EE). OCs with 150 mcg of desogestrel and 30 mcg of EE slightly increased C-peptide levels, but insulin and glucose level increases were marked. Thromboembolitic changes via clotting factor alterations were similar after the use of OCs with 30-35 mcg EE, triphasics, or new progestins. LNG implants (Norplant) significantly reduced HDL cholesterol and slightly lowered HDL II, while somewhat increasing serum glucose and insulin.