Progesterone supplementation is often given to assist women attempting to become pregnant, especially as a part of IVF and IUI regimens.
Progesterone and Pregnancy
Progesterone is essential to a healthy pregnancy. It is necessary to both conceive and maintain a pregnancy. One of its roles is in thickening the lining of the uterus so that a fertilized egg can implant. The thickened lining allows blood vessels to grow that will supply nutrients and oxygen to the developing embryo. The corpus luteum will continue producing progesterone until around the 10th week of pregnancy. Throughout pregnancy, progesterone levels will continue to rise. A woman who is pregnant has progesterone levels that can be as much as ten times higher than a woman who is not pregnant.
In Vitro Fertilization (IVF) / Intrauterine Insemination (IUI)
Other medications used during IVF can result in decreased production of progesterone. These medications include Lupron, Antagon, and Cetrotide as part of an ovarian stimulation regimen. Without hormonal support during the luteal phase subsequent to IVF cycles there is often early luteolysis, followed by premature decline of estrogen and progesterone levels. IVF treatments are less successful when these abnormalities present. For these reasons, progesterone therapies (injections/cream/oral) are prescribed for patients undergoing IVF. Studies have shown that IVF cycles that include the use of progesterone have higher pregnancy rates. The drugs that are used to help ovulation are usually taken first, followed by progesterone. Progesterone is usually used the day that eggs are retrieved.
For intrauterine insemination (IUI), progesterone may similarly help to prolong the lifespan of the uterine lining which can give more time for the egg to be fertilized.
Progesterone Dosage Forms
Progesterone for IVF is generally prescribed in two ways – intramuscular injection and vaginal suppositories. Oral progesterone is sometimes preferred by patients. However the bioavailability of oral progesterone may be lower than other methods. The oral bioavailability of micronized progesterone is 10% due to first-pass metabolism.
The intramuscular injection of progesterone is given in the butt, hip, or thigh. An alternative to injections is to use vaginal administration. This may be helpful for women who can not tolerate injections or who are allergic to some part of the injectable form. It can sometimes be difficult to give injections to yourself if that is required. Vaginal suppositories can be made by a compounding pharmacy in any dosage required and are preferred by some women.
Vaginal application of progesterone may result in higher levels of progesterone when administered after IUI. However both vaginal and intramuscular forms are effective and have been shown to have comparable patient satisfaction. It has been found that implantation rates are about 46 percent regardless of the type of progesterone used.
The side effects of a vaginal progesterone formulation usually only include mild irritation. For intramuscular injection the side effects may include local reactions like pain around the injection site and bruising. Systemic side effects can also sometimes occur but in the case of fertility treatments the therapy does not continue indefinitely (as with treatment for menopausal symptoms).
Other forms of progesterone that may be prescribed include vaginal cream/gel and oral capsules. Besides the low bioavailability of oral progesterone, it also may result in more unwanted side effects. Cream or gel is an alternative to a suppository and can also be made by a compounding pharmacy.
Articles
Intramuscular progesterone (Gestone) versus vaginal progesterone suppository (Cyclogest) for luteal phase support in cycles of in vitro fertilization–embryo transfer: patient preference and drug efficacy – Fertility Research and Practice
Clinical use of progesterone in infertility and assisted reproduction – AOGS