What is Progesterone?
Progesterone is a hormone that is vital for pregnancy. It helps to prepare the uterine lining for an embryo to implant.
So just how does it work? After a woman ovulates, the ovary undergoes dramatic hormonal changes, and it begins making large amounts of progesterone and estrogen, another hormone. These hormones support the inner lining of the uterus (called the endometrium) and keep it from shedding and causing a period. The part of the ovary that makes these hormones is called the corpus luteum.
The corpus luteum survives for about two weeks after ovulation, and it then degenerates if no pregnancy is detected. Once it degenerates, progesterone levels drop and the lining sheds. If a pregnancy occurs, however, then the corpus luteum survives through the first trimester, making more progesterone that prevents a menstrual cycle from occurring.
Luteal Phase Deficiency
In some women the ovaries do not make enough progesterone, making early pregnancy more difficult to maintain. This lack of progesterone is called a luteal phase deficiency.
Historically, there have been tests that evaluate whether women have a luteal phase deficiency. However, this is hard to measure accurately. Blood levels of progesterone may vary throughout the day, and progesterone levels seen within the uterus itself may not correlate with progesterone levels observed in the blood. Therefore, some doctors supplement women attempting to achieve pregnancy with progesterone in many cases of infertility or recurrent pregnancy loss, even if tests are normal.
Progesterone supplementation is prescription medication that is taken after ovulation. The lining of the uterus responds to the progesterone medication, thickening and preparing for pregnancy.
In IVF cycles, the supplementation is thought to be even more critical. There may not be enough progesterone made by the ovary during an IVF cycle, and so more progesterone is routinely prescribed.
Because progesterone is a naturally occurring compound within the human body, it is believed that progesterone supplementation does not harm the developing human embryo. The supplementation often ends around 10 weeks after conception. At this point, the placenta is making the lion’s share of progesterone needed and is able to support the pregnancy.
If you have additional questions about progesterone supplementation or are experiencing infertility or recurrent pregnancy loss, please call Fertility Associates of Memphis at 901-747-2229 to schedule an appointment with one of our reproductive endocrinology and infertility specialists.