Biological effects of eleven combined oral contraceptives on serum triglycerides, gamma-glutamyltransferase, alkaline phosphatase, bilirubin and other biochemical variables.

The objectives of this paper are to update and quantify the biological effects of the most commonly used oral contraceptives (OC) on 15 biochemical tests currently determined in clinical laboratories and to compare these effects between the different types of OC. The sample population was constituted by 1604 women using combined OCs and the control group comprised 3466 women in the same age range not taking medication. Women taking OC were divided into 11 groups according to the estrogen/progestogen combination. The effects of OCs were studied after adjustment for age, weight, height, body mass index and alcohol and tobacco consumption. The changes observed with the new progestogens were less important than in the past. In comparison with the controls, the mean serum triglyceride concentration was significantly increased by +8.5% to +36.0% (p<0.05 to p<0.001) in each group while those of total cholesterol and gamma-glutamyltransferase were increased only in 3 and 4 estrogen/progestogen combinations respectively. Conversely, the mean concentrations of alkaline phosphatase, total bilirubin, phosphate and albumin were significantly decreased. Using a discriminant analysis, three main groups according to the type of progestogen were defined: cyproterone acetate, DL-norgestrel and levonorgestrel, and all other progestogens. The changes in serum triglyceride concentration induced by OC intake must be considered by the clinician and are useful for taking a clinical and risk decision in an individual woman.