The Types and Uses of Fertility Drugs
“Fertility drug” is a term for medications that are prescribed by specialists to assist couples in achieving their reproductive goals. This includes, but is not limited to, medications used for ovulation induction (OI) or in controlled ovarian hyperstimulation (COH) during IVF.
How these drugs work varies, depending on the drug, and can range from inhibition of receptors in the brain to direct mimicking of hormones that occur naturally in the body. Depending on the medication, administration may be oral, vaginal, or via a self-administered injection.
Before beginning any medication or protocol, your physician will meet with you to discuss your medical history as well as that of your partner, if one is involved. A complete diagnostic work up, including physical exam and laboratory evaluation, should always be performed prior to the start of any protocol. If a cause for your difficulty in achieving pregnancy is identified, your provider will utilize a protocol directed at optimizing your chances for fertility based on your diagnosis.
Fertility Drugs That Stimulate the Ovaries (STIMS)
Though they work differently in the body, stimulating medications or STIMS have the same goal in common: that is to increase the amount of circulating follicle stimulating hormone (FSH) and luteinizing hormone (LH).
While the way medications in this category act on the body differs, they all increase the amount of circulating FSH and LH. Increasing concentrations of these hormones, in turn, stimulates your ovaries to produce 2 or more follicles. Depending on what type of protocol you are using (i.e., for ovulation induction or for ovarian stimulation prior to egg retrieval in IVF), the amount of medication required will vary, as well the expected ovarian response.
Medications that fall into this category: Clomiphene Citrate, Letrozole (both often used in ovulation induction), Gonal F and Follistim (both follitropins that are preparations of FSH).
Fertility Drugs that Prevent Premature Ovulation
As part of your fertility treatment, your physician may want to incorporate medications that prevent premature ovulation. These medications are often used during IVF cycles, when the goal is for equal recruitment and growth of as many follicles as possible prior to ovulation. By giving a medication that can help to prevent the LH surge that occurs just before ovulation, there may be more opportunity to allow a greater number of follicles to grow.
Medications that fall into this category: Lupron, a GnRH agonist, or Cetrotide or Ganirelix, a GnRH antagonist.
Fertility Drugs that Cause Ovulation to Occur
Some women do not ovulate regularly. When ovulation is irregular and uncertain, optimal timing for intercourse or insemination can prove challenging. For this reason, medications are sometimes used which induce ovulation at a specific time. Generally, once a follicle is mature (at least 18mm in diameter), administration of this type of medication will induce ovulation approximately 24 to 36 hours after it is given.
Medications that fall into this category are: Ovidrel, Pregnyl, and Novarel.
Fertility Drugs that Promote Implantation
After ovulation has occurred, what remains of the follicle within the ovary is called a corpus luteum. The corpus luteum secretes progesterone which, among other things, stabilizes the lining of the uterus and prepares the lining for a potential pregnancy. In women with low progesterone levels or for those proceeding with a frozen embryo transfer, in which a corpus luteum has not preceded the embryo transfer and therefore natural progesterone is not available, a progesterone supplement may be prescribed in order to help support the pregnancy. This medication may be injected, taken orally, or as a vaginal suppository.
Medications that fall into this category are: Progesterone in Oil, Endometrin, Crinone, and Prometrium.
Dr. Jenna Friedenthal is a Fellow in Reproductive Endocrinology and Infertility at Reproductive Medicine Associates of New York. Dr. Friedenthal completed her undergraduate education at Yale University. She went on to complete her medical degree from the Albert Einstein College of Medicine with Distinction in Research. While in medical school, she received the Senior Research Fellowship award for her research accomplishments in reproductive endocrinology and immunology. Dr. Friedenthal then completed her residency training in Obstetrics and Gynecology at New York University. During her residency training, Dr. Friedenthal received the Mortimer Levitz Best Basic Science Award for her research on pre-implantation genetic testing.