What Is Estradiol and Progesterone?

Estradiol and progesterone are hormones naturally produced by the body, and they are also created in laboratories. These manufactured versions are used in numerous drugs or other treatments that may provide birth control or that can treat some of the symptoms associated with menopause. Estradiol is a form of estrogen and is the most common type of prescription estrogen supplementation, but progesterone can be made in a variety of forms that have different names, like norethindrone, norgestimate, and levonorgestrel. Regardless of the name, these forms of progesterone have similar side effects and elevated risks for certain complications.

In the body, an appropriate supply of estrogens and progesterone control a woman's menstrual cycle, among other things. Progesterone helps to create the lining of the uterus that would help sustain a pregnancy. Estrogen stimulates other hormones, like luteinizing hormone, that control the release of eggs. The production of these two hormones falls as women age and approach menopause.

Scientists have long known that taking additional estradiol and progesterone affects ovulation and reduces the likelihood of conception. Combination birth control bills or skin patches that contain these two hormones in a greater than normal supply can suppress both ovulation and the buildup of a sustaining lining in the uterus. Such medications are very effective when used perfectly, and confer a 99% chance of preventing pregnancy. They also may help to address conditions like ovarian cysts, irregular periods, or severe premenstrual symptoms.

Since these hormones naturally decline with age, estradiol and progesterone may also be recommended during or slightly before menopause when symptoms of reduced hormones may be severe. For example, vaginal dryness, hot flashes, mood changes, or a higher risk for osteoporosis may be addressed with hormone replacement therapy (HRT). Until recently, HRT was often prescribed, but studies on its increased risks for cancer now make it a less popular, though still available, option.

There are serious risks associated with using estradiol and progesterone at any time of life. They tend to elevate chances of blood clotting, and the possibility of having a stroke. Any drug with these two hormones is not recommended for women over 35 who smoke, or for those with blood clotting issues or heart disease.

Moreover, women with a history of breast or other reproductive cancers are at an elevated risk if they take these medications. As mentioned, a higher chance of developing breast cancer has been established for all women who use these two hormones to treat menopausal symptoms. HRT with just estrogen tends to be associated with an elevated risk of uterine cancer, too. This is slightly reduced when individuals use estradiol and progesterone together. Still, the increased chance of breast cancer remains the same, whether one or both hormones are used.

Some serious side effects may occur when estradiol and progesterone are taken together. These include severe allergy, and development of cancers, blood-clotting, or cardiovascular diseases. More benign adverse reactions are bloating, headaches, nausea, and breakthrough bleeding, even if menopause is complete. Doctors advise patients to carefully consider the risks and benefits of using these two hormones, particularly for HRT, to determine if estradiol and progesterone are the best choice for treating symptoms.