Fertility Drugs- An Overview

A variety of fertility drugs, and procedures, are now available to treat most conditions that cause female infertility. Unfortunately, there are few effective pharmaceutical products to treat male infertility.  The “sperm enhancers” touted on the Internet, which promise to increase sperm count, improve sperm “quality” or produce “stronger sperm” have minimal or no clinical data to support their claims. 

Drugs such as Clomid® and follicle stimulating hormone (FSH), work to enable, regulate, or enhance ovulation.  FSH stimulates the ovaries directly while Clomid® works at the hypothalamus. In order to understand how these products achieve their effects, it is necessary to have a basic understanding of the processes involved in follicular development and ovulation.

Ovulation is controlled by a series of hormonal interactions occurring at the hypothalamus, a small gland located at the base of the brain, and the pituitary gland. The hypothalamus can be compared to a thermostat, measuring various hormone levels and adjusting production accordingly.

The hypothalamus produces gonadotropin releasing hormone (GnRH), which travels to the pituitary and influences the production and release of FSH and luteinizing hormone (LH). Increased levels of GnRH stimulate the production of FSH, which directly stimulates follicular recruitment and development.

As healthy follicles develop, they produce increasing amounts of estrogen. The hypothalamus, in its role as a regulator, measures estrogen levels and adjusts GnRH output accordingly. Once the hypothalamus “judges” the follicles to be mature, based upon estrogen levels and other factors, it stimulates the pituitary gland to produce a spike in LH production, which stimulates the release, or ovulation, of the egg from the ovarian follicle.

The endometrium must thicken and become more vascular in order to accept and support an embryo. Estrogen and progesterone stimulate endometrial development. Progesterone is produced by the “leftover follicle” which becomes a structure known as the corpus luteum. Elevated progesterone levels are an indication that successful ovulation has occurred. Once a pregnancy is established, progesterone is produced by the placenta.

Fertility drugs affect these processes and are discussed on their respective Web pages.

Fertility Drugs

• Clomid®, clomiphene citrate
• FSH, Gonal-F®, Follistim®, Bravelle®
• GnRH Agonists, Antagonists Lupron®, Ganirelex®
• hCG, Pregnyl®, Novarel®
• Letrozole, Femara®
• Metformin, Glucophage®
• Parlodel® (bromocriptine)
• Progesterone