Clomiphene, known under various brand names including Clomid, Serophene, and Milophene, is a drug that stimulates ovulation. It is prescribed to women with irregular or even absent ovulation (anovulation) to “jump start” the normal cycle or to improve the timing of ovulation in preparation for intercourse or intrauterine insemination.
Below, you'll learn how it works and the success rates of taking it.
How does Clomiphene Work?
Clomiphene works by binding to receptors in the hypothalamus that would normally detect estrogen. The balance of estrogen along with two other hormones - follicle stimulating hormone (FSH), and luteinizing hormone (LH) - controls the cycle of ovulation. If the hypothalamus cannot properly detect estrogen, production of the other hormones continues for longer, stimulating the development of follicles in the ovaries and promoting ovulation.
Because it affects the levels of three critical hormones, Clomiphene does have several side-effects. In addition to more typical concerns like nausea and headaches, these effects include:
- If you take a fertility test that measures levels of LH soon after clomiphene treatment, there is a high chance of a false positive. Keep this effect when tracking ovulation.
- Clomiphene can reduce the production of cervical mucus, potentially keeping sperm from entering the uterus.
- One in five patients may experience reduced estrogen production, resulting in a thin uterine lining. If the lining is too thin, the fertilized egg may not be able to implant.
Impact on Fertility
Clomiphene has been a reliable treatment for infertility due to poor ovulation for over 40 years. After three ovulations, 50% of women taking clomiphene can be expected to conceive. For women suffering from polycystic ovary syndrome (PCOS), a common cause of anovulation, treatment with clomiphene results in ovulation in 80% of cases. 30% - 40% of those cases result in pregnancy.
Clomiphene increases the chance of becoming pregnant with twins, because the increase in ovulation may cause the body to release more than one egg at a time. For pregnancies following clomiphene treatment, the chances of having twins is about 10%, compared to the 3% chance for pregnancies overall.