Progesterone is a hormone produced by the ovaries that helps maintain a normal menstrual cycle. By preparing the lining of the uterus for embryo implantation, progesterone also plays a critical role in maintaining the early weeks of pregnancy. At about the eighth week of a normal pregnancy, the placenta takes over the role of producing progesterone for the remainder of the pregnancy. Progesterone helps relax the muscles in the lining of the uterus and also helps the breasts develop in preparation for milk production after the birth of a baby.
Some women have ovaries that don’t make enough progesterone. These women may experience difficulty conceiving or maintaining a pregnancy once conception occurs. For such women, progesterone supplements may be prescribed. When given after ovulation, progesterone supplements act on the lining of the uterus to make it thick and rich in nutrients in preparation for implantation of the embryo. Progesterone supplements may also be prescribed early in pregnancy if a woman’s blood levels of progesterone are low or if she has a history of repeated miscarriages. Such supplements are usually prescribed for several weeks.
Progesterone supplements can be taken orally, as injections, or as vaginal suppositories. While most oral progesterone supplements are capsules, there are some supplements called troches that are placed under the tongue to dissolve. Progesterone injections are usually given in the buttock area, and some women report that they are more painful and cause more discomfort than many other types of injections. A progesterone suppository is inserted into the vagina. It may cause some leaks; this is normal and does not mean that progesterone is not absorbed. Progesterone supplementation can cause some common but transient side effects, including nausea, tiredness, and breast tenderness.
