A primer on ovulation induction

Ovulation induction uses medication to help the ovaries develop and release an egg. It is often one of the first treatments offered to people who do not ovulate regularly.

Why ovulation can be irregular

Common causes of irregular or absent ovulation include polycystic ovary syndrome (PCOS), thyroid or pituitary problems (such as high prolactin), being significantly under- or overweight, and very intense exercise or eating disorders. ACOG lists problems with the thyroid or pituitary gland among the causes of infertility that a specialist will look for.

The main medications

• Clomiphene citrate: taken by mouth, it blocks estrogen's effects in the brain, prompting the body to release more of the hormones that stimulate the ovaries. MedlinePlus lists flushing, upset stomach, breast discomfort, and headache among its side effects.
• Letrozole: an aromatase inhibitor that works by decreasing the amount of estrogen the body makes, according to MedlinePlus. It is approved for breast cancer and is used off-label for ovulation induction.
• Gonadotropins: injectable hormones that stimulate the ovaries directly, usually used when oral medications do not work.

Risks to know about

ACOG notes that multiple pregnancy is a risk with clomiphene, aromatase inhibitors, and gonadotropins, with the highest risk from gonadotropins. Ovulation stimulation, especially with gonadotropins, can also cause ovarian hyperstimulation syndrome (OHSS), which is usually mild but occasionally needs hospital care. That is why cycles are monitored, and a cycle may be postponed if too many eggs are developing.

What about newer research and patents?

Researchers continue to study new drug combinations and protocols, and some are patented. A patent shows that an idea has been claimed, not that it works or is safe; new approaches need clinical trials before they become treatment. If you are offered something new, ask whether it is part of a trial and what evidence supports it.

Questions to ask your doctor

• What is likely causing my irregular ovulation?
• Which medication do you recommend, and why?
• How will you monitor my response and lower the risk of twins or OHSS?
• How many cycles should we try before considering another approach?