Ovulation is regulated by a complex interaction of hormones controlled by the hypothalamus, a small gland located at the base of the brain. If a woman is experiencing infertility, a doctor may prescribe fertility drugs, most of which help stimulate or regulate ovulation.
Types of fertility drugs
Clomid and Letrozole
Clomid or Letrozole is often prescribed as a first line treatment by the OB/GYN. These medications are most likely to work within the first three ovulatory cycles, and therapy beyond this time is usually not recommended. They are both oral medications that induce, or regulate, ovulation. Clomid exerts its effects at the hypothalamus, the gland that signals the pituitary gland to produce FSH and LH. FSH stimulates the ovaries directly to produce eggs/follicles, and the response is dose related.
Letrozole is often given to patients with Polycystic Ovarian Syndrome, or PCOS. Letrozole blocks the formation of estrogen in the body, which sends a message to the pituitary gland to increase the amount of FSH. FSH stimulates the ovaries directly to produce eggs/follicles.
FSH (e.g., Gonal-F, Repronex, Follistim, Menopur) stimulates the ovaries directly, causing the recruitment of multiple follicles. FSH should only be used by reproductive endocrinologists—fertility specialists thoroughly trained in its administration. This is especially true for women who may be suffering from PCOS and who can have exaggerated responses to FSH. FSH can cause the development of many eggs within the ovarian follicles; this is critical for in vitro fertilization (IVF), where retrieving multiple eggs is desired. The stimulation must be carefully monitored via ultrasound and blood work to assess the number and size of follicles and estradiol hormone levels.
Metformin for PCOS treatment
Metformin has gained widespread use in the treatment of women with PCOS. Metformin is known as an insulin sensitizing drug or an antiglycemic and is also used in treating pre-diabetes and type II diabetes. Clomid is also frequently used in conjunction with Metformin as a treatment for failed ovulation.
Lupron, Antagon, Cetrotide
Lupron is a GnRH agonist that is often used in IVF cycles. It can be used during the cycle to prevent natural ovulation, or it can be used as a trigger injection for final maturation of eggs/follicles prior to an egg retrieval procedure.
Progesterone to support endometrial growth
Progesterone’s role in the ovulatory cycle is to help prepare and support the endometrium (lining of the uterus) to accept and nourish a developing embryo. Progesterone is initially produced by the leftover follicles on the ovaries, the corpora lutea, and later by the placenta. When insufficient progesterone is produced, it’s sometimes called a luteal phase defect. Oftentimes, this condition is effectively treated with externally administered progesterone. Women undergoing IVF cycles with Lupron, Antagon or Cetrotide regulation always receive supplemental progesterone.
hCG to stimulate and cause ovulation
hCG is known as the pregnancy hormone, and rising levels indicate that a pregnancy has been established. hCG can also prepare the follicles for and initiate ovulation and egg maturation; this is because the body responds to a spike in hCG levels in the same manner as the LH surge. hCG is administered to women undergoing ovarian stimulation when the physician judges that the follicles are mature. In an IVF cycle, the hCG injection is given and an egg retrieval is scheduled accordingly, usually 34 to 36 hours later. Similar protocols are followed for women undergoing stimulated intrauterine insemination (IUI) cycles, using great caution to help control possible high order (greater than 3) multiple births.
Luveris is produced by genetically modified mammalian cultures and is identical to the body’s luteinizing hormone (LH). It is indicated for stimulation of follicular development in infertile hypogonadotropic hypogonadal women with profound LH deficiency. However, it may be used off label to prepare the follicles for and initiate ovulation and egg maturation. Luveris could also be used with IVF drug stimulation protocols in some women to improve egg quality.
Parlodel or Dostinex
Parlodel (bromocriptine) and Dostinex (cabergoline), are dopamine-agonist medications used to treat women with high levels of prolactin, or hyperprolactinemia. Hyperprolactinemia can impact the natural menstrual cycle and prevent normal ovulation. Dostinex may also be used at the end of an IVF cycle to help prevent ovarian hyperstimulation syndrome, or OHSS, in women at risk.