Fertility Drugs
Many fertility drugs are now available
to help couples conceive. Most of these medications
stimulate ovulation in the female and include fertility
drugs, such as follicle
 stimulating
hormone FSH (Gonal-F, Follistim, Repronex, Menopur),
Clomid, and Glucophage
(corrects insulin imbalance). Other fertility drugs
correct hormonal imbalances, such as Parlodel, which lowers the level of the
hormone prolactin.
The Ovulatory Cycle
In order to understand how fertility drugs exert their actions, it is necessary to have a basic understanding of the ovulatory cycle. Every month the normal fertile female undergoes hormonal changes (the hypothalamic-pituitary-adrenal axis) associated with egg recruitment, development, ovulation, fertilization and embryo implantation.
The hypothalamus is a gland located at the base of the brain responsible for regulating hormone levels, much like a thermostat. During the first few days of the ovulatory cycle, the hypothalamus signals the pituitary to produce follicle-stimulating hormone (FSH). This "signal" is sent by gonadotropin releasing hormone (GnRH). Increasing levels of GnRH causes increased production of FSH.
FSH
directly stimulates the follicles on the ovary,
each one of which contains an egg. As healthy follicles
develop, they begin to produce estrogen. The hypothalamus
"measures" the levels of estrogen and adjusts
the production of FSH accordingly. Once the follicles
are mature, the hypothalamus signals the pituitary
gland to produce a surge of luteinizing hormone (LH),
which stimulates ovulation.
The follicular structure remaining
after ovulation is known as the corpus luteum and
it begins to produce progesterone.
Estrogen and progesterone stimulate the growth and
development of the lining of the uterus (endometrium).
The endometrium must thicken and become more vascular
to accept the developing embryo. Once the embryo has
implanted, the placenta begins to produce additional
progesterone.
Fertility drugs affect one or more of these ovulatory cycle processes. We discuss the most commonly used fertility drugs:
Unfortunately, there are few fertility medications proven effective in the male. Medications are rarely effective unless there are specific hormone abnormalities, which is very infrequent.
Mild male
infertility is effectively treated using intrauterine
insemination (IUI) and moderate to severe male
factor is treated with in
vitro fertilization and intracytoplasmic
sperm injection.
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