Effect on plasma lipids and lipoproteins of postmenopausal oestrogen therapy with added dydrogesterone.

In a prospective, randomized, cross-over study, 14 postmenopausal women completed 9 months of treatment with conjugated equine oestrogens, 1.25 mg daily. Seven women added dydrogesterone 20 mg daily for 12 days during months 2, 3 and 4, and then 10 mg daily for an identical time in months 5, 6 and 7. The other seven women added the two dydrogesterone doses in reverse sequence. No dydrogesterone was taken during months 8 and 9. Lipids and lipoproteins were measured before treatment and at the end of months 4, 7 and 9. Lipids were also estimated in an untreated (reference) group of eight postmenopausal women on two occasions 6 months apart; these showed significant changes in HDL2- and HDL3-cholesterol. In the treatment group, HDL-cholesterol and apolipoprotein (apo) A1 were significantly higher and LDL-cholesterol and apo B were significantly lower at months 4, 7 and 9 compared with baseline values. Triglyceride levels were increased significantly over baseline values, but remained within the normal range. No significant differences between the two dydrogesterone doses were observed on any lipid and lipoprotein fraction, nor were there any differences between the oestrogen-only and oestrogen/dydrogesterone treatment phases. Dydrogesterone appears to cause little, if any, lipid and lipoprotein changes and assessment in a larger population of postmenopausal women is warranted.