Progesterone is produced by the ovaries after ovulation. Progesterone is a hormone that prepares the endometrium (the uterine lining) for the fertilized egg (embryo) as it arrives from the fallopian tube. Insufficient progesterone may result in early pregnancy loss and infertility which is a condition known as a “luteal phase defect”. Progesterone, gonadotropins, and/or Clomid are three possible treatments for a luteal phase defect. The results of treatment with these fertility drugs are about the same with successful pregnancy and range from 50-60%.
Progesterone may be administered by daily injection, vaginal suppositories or in pill form and progesterone treatment is usually begun 2-3 days after ovulation. It is very important to begin treatment with this fertility drug at the right time. Progesterone treatment prior to ovulation may actually interfere with the chance for conception. If progesterone treatment is started more than 4 or 5 days after ovulation it may not be effective.
A clear rise in the basal body temperature graph and/or change in the urinary ovulation predictor kit will help pinpoint the time of ovulation. Progesterone treatment should begin 3 or 4 days after the ovulation kit change or 2-3 days after the temperature is clearly "up". After progesterone therapy begins, the temperature will be high due to the medication. Progesterone is continued for about 2 weeks.
The progesterone treatment is stopped if the menstrual period begins and the next cycle begins. If the menstrual period is more than 3 or 4 days late, a home urine pregnancy test should be performed. If the home pregnancy test is negative, progesterone is stopped and menses should begin in a few days. If conception occurs while using progesterone suppositories, it will be necessary to continue treatment through the first 10 weeks of pregnancy. Low levels of progesterone can cause early pregnancy loss during that time. Progesterone is produced by the placenta after about 10 weeks.
The fertility drug progesterone has one theoretical recognized treatment risk. Other forms of progesterone have been associated with congenital anomalies of babies exposed to the drug during the first 10 weeks of pregnancy. These "other forms" are different from the progesterone prescribed for infertility treatment.
There is no clear evidence that the progesterone used for infertility treatment causes congenital anomalies in offspring. We acknowledge a theoretical risk of major organ anomalies with this progesterone therapy. Progesterone has been used to support pregnancies for decades and is a common therapy
