What is Progesterone?

Progesterone is a hormone secreted by the ovary after ovulation

Progesterone is only administered after ovulation is known to be complete (i.e., three days after an LH surge or HCG injection, two days after insemination is completed, or the evening following IVF egg retrieval.)

How does Progesterone work?

Progesterone changes the lining of the uterus to make it more receptive for implantation and it is responsible for slightly raising the body temperature during the second half of a women's menstrual cycle.

You will receive progesterone either in the form of an intramuscular injection or vaginal suppository. Your dosage by injection or suppository will be discussed with you. Some patients prefer injection while other patients prefer to avoid injection and will tolerate the feelings associated with suppository use. For those patients bothered by the messiness of suppositories, we suggest wearing a pad to absorb the discharge associated with the suppositories. If intercourse takes place, insert the suppository afterward.

You must continue your progesterone therapy until your pregnancy blood test result is known. And since progesterone may delay the onset of your period, a pregnancy test should be scheduled for two weeks after ovulation, regardless of whether you are bleeding.

Side Effects

Occasionally, women will complain about an itchy discharge with vaginal progesterone use. It is also possible to develop a yeast infection while using this hormone. This is not a serious complication and it will not affect fertility. If you are bothered by increased discharge accompanied by an itch or raw feeling, then please let us know.

Progesterone therapy is a standard part of our fertility medication / insemination program, as well as our IVF and egg donation program. We have had many years experience using this medication and feel comfortable recommending it to you as part of your therapy.


The progesterone medication used in your prescription is similar to natural progesterone produced by your ovary. Please note that progesterone is related to a variety of hormones known as progestins (for example, Provera; or the progestin in the birth control pill). All progestins are required by law to have a package insert that describes some studies that suggest a slight increase in birth defects associated with its use.

Please note that all of these studies have involved synthetic or manmade progesterones and do not describe the progesterone that we use. There appears to be no increase in birth defects linked to the more natural progesterone ("progesterone" in oil or "progesterone" in suppositories). These studies also involved a higher dose, and were administered at a later time in the pregnancy.