Progestin replacement in the menopause: effects on the endometrium and serum lipids

The benefits of estrogen replacement therapy (ERT) in the menopause have been well demonstrated and are of significant importance, particularly with regard to prevention of osteoporosis and reduction in cardiovascular morbidity and mortality. The addition of a progestin to ERT is advocated in patients with a uterus to minimize the risk of endometrial hyperplasia and cancer. Although progestins can have adverse effects on serum lipids, it is unclear whether or not these effects negate the cardioprotective effects of estrogen. Progestins are an important part of hormone replacement therapy (HRT) regimen in patients with an intact uterus. The minimum dose and duration should be given to offset potential adverse effects on serum lipids while affording adequate protection of the endometrium. Both continuous and sequential progestin regimens appear to be efficacious. The newer progestins may offer increased flexibility in minimizing progestin side-effects while protecting the endometrium. Other regimens, such as less than monthly progestin administration, may offer another alternative to achieve these goals. Future studies in these areas are warranted.