Taking hormone replacement therapy, or HRT, for menopausal women is a complicated health issue. Once thought to protect against heart disease, conjugated, or synthetic, estrogens such as Premarin were taken by as many as 13 million women in the United States in 2002, nurse-practitioner Michelle Pick states on her website women to women. A large study released that year by the Women's Health Initiative indicated an increase in certain cancers, as well as an increase in cardiovascular complications in women taking Prempro and other HRT. Women taking HRT must carefully weigh the risks and benefits.
Endometrial Hyperplasia
Premarin, which contains several types of synthetic estrogen, can thicken the uterine lining. In menopausal women, a constant build-up of the lining without the monthly shedding that normally occurs can increase endometrial hyperplasia. Endometrial hyperplasia increases the chance of developing uterine cancer. Irregular bleeding or spotting can also occur. Taking a progestin, a synthetic form of progesterone, along with estrogen produces a withdrawal bleed each month, which thins the lining and reduces the risk, Drugs.com advises.
Cardiovascular Disease
Premarin and other HRTs can increase the risk of cardiovascular disease in women, but risks vary. Women who undergo early menopause because of premature ovarian failure or surgical removal of the ovaries have a higher risk of cardiovascular disease even if they don't take HRT, MayoClinic.com explains. Women who become menopausal in their 40s and 50s appear to have less risk of cardiovascular disease while on Premarin, at least until they reach the age of 60, when the risk increases. Premarin, which does not contain progestins, can increase the risk of stroke or blood clots, particularly in women who smoke. Conjugated estrogens without added progestin didn't increase the risk of other types of heart disease in the study, according to MayoClinic.com.
Birth Defects
The Food and Drug Administration classifies Premarin as a category X drug, meaning it should not be taken in pregnancy. Women who get pregnant while taking Premarin have a higher incidence of having children with birth defects, Drugs.com warns. Breastfeeding women should also not take Premarin, which passes through breast milk and could harm a nursing child.
Breast Cancer Exacerbation
Women with breast cancer should not take any form of estrogen, which can accelerate the growth of cancerous cells. While women taking estrogen plus progestin HRT had a slight increase in breast cancer risk, women taking just synthetic estrogen did not have an increase in breast cancer, MayoClinic.com reports.
