Clomid or Femara?

Women often ask our doctors whether they need Clomid or Femara. Our Austin fertility center is here to answer this important question.

All about Clomid

Clomiphene citrate (Clomid, Serophene) is an oral medication that doctors have used to induce ovulation for almost 40 years. Commonly, doctors combine intrauterine insemination (IUI) with this medication. This is important to know when deciding if a patient needs Clomid or Femara.

Clomiphene is a very weak estrogen that attaches to the estrogen receptor in the hypothalamic-pituitary area. The medication acts like an “anti-estrogen”. The brain interprets this as the quantity of estrogen circulating in the body is low. Therefore, sends a signal to the pituitary to stimulate the ovary to work harder.  For most women who do not ovulate, this medication commonly will make them ovulate.

Unfortunately, this anti-estrogen action can affect the cervical mucus and the endometrium. The result is that there is less cervical mucus produced and the sperm may have a harder time penetrating the mucous. Also, the endometrial liming may not develop as well and this could interfere with an embryo implanting. In general, the positive effects of clomiphene outweigh the negative effects.

What to know about Femara

Letrozole (Femara) was developed to be used primarily to treat certain kinds of breast cancer in postmenopausal women. Letrozole is an aromatase inhibitor. Aromatase is an enzyme that converts estrogen precursors (androgens) into estrogen. The medication works by reducing the production of the total amount of estrogen in the body.

Letrozole can also induce ovulation in the same manner as clomiphene. Letrozole inhibits the conversion of androgens to estrogens. When this happens, the estrogen level in the body drops and the hypothalamus tells the pituitary to stimulate the ovary to work harder. Commonly, doctors combine intrauterine insemination (IUI) with this medication.

In contrast to clomiphene, this medication does not have the anti-estrogen effect. It often produces better endometrial development. Theoretically, letrozole would be better for patients who have used Clomid and experienced poor endometrial development. Experience with this medication reveals the pregnancy rates are very comparable to clomiphene. Also, the multiple birth rate with letrozole is lower.

Get help deciding whether you need Clomid or Femara

When considering whether you need Clomid or Femara, please ask your physician which one is better for you. Contact us to learn more.