Agonists or antagonists during IVF?

This review compared the use of gonadotropin-releasing hormone (GnRH) agonists and antagonists in poor ovarian responders undergoing in vitro fertilization (IVF).

In vitro fertilization (IVF) is a complex process which requires tight medical control over the ovulatory cycle. To achieve such control, the normal action of ovulatory hormones in the body must first be suppressed. The most common drugs used to achieve this suppression are GnRH agonists. In recent years, GnRH antagonists have been developed and have risen in popularity among fertility physicians. The use of GnRH antagonists during IVF requires shorter treatment cycles, and is known to reduce the risk of complications such as over-stimulation of the ovaries. However, GnRH antagonists are also considerably more expensive. While GnRH antagonists have proven useful in the management of many infertility cases, little is known regarding their effect on the success of IVF among women with poor ovarian function.

This meta-analysis (an analysis of results combined from several similar studies) reviewed 12 studies, including a total of 1,332 infertility cases. At the end of treatment cycles, both endometrial thickness (the thickness of the uterus lining) and estrogen levels (indicating growth of follicles in the ovaries) were significantly lower among women treated with GnRH antagonists compared to those treated with GnRH agonists. Furthermore, fewer oocytes (eggs ready to be fertilized) were retrieved from women receiving GnRH antagonists compared to those receiving GnRH agonists. Despite these results, success and failure rates of IVF cycles were not significantly different between the two groups.

This analysis concluded that the use of GnRH agonists appears to be superior to the use of GnRH antagonists among women with poor ovarian function undergoing in vitro fertilization.