Biochemical effects in women following one year's exposure to a new triphasic contraceptive--I. chemistry profiles.

1. Thirty-nine nonsmoking women, 14 who had never used oral contraceptives and 25 who had a prior history of contraceptive use were placed on a 1-year regimen of oral triphasic contraception containing a new progestin. 2. Biochemical determinations of 21 different variables were made at baseline, 3 months, 6 months, and 12 months of exposure. 3. Most of the significant changes were in those women with no prior exposure to contraceptives. 4. Thyroxine increased and T3 decreased, as did urinary cortisol. No changes were noted in the CBC, hematocrit, or platelet count. Slight increases in cholesterol and triglycerides resulted, with small nonsignificant increases in LDL also occurring; this increase was also noted for HDL. 5. The experimental contraceptive seems to have a very minimal influence on chemistry profiles, suggesting a favorable biochemical response to the progestin.