IVF Medication Less Effective for Obese Women

Obese women on cetrorelix for IVF may face premature ovulation because of reduced medication effectiveness

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Many women choose in vitro fertilization (IVF) when they have trouble getting pregnant. A recent study investigated whether obesity affects how well IVF works.

Researchers recruited obese women and normal-weight women to participate in this study.

Each of the women received a dose of a medication that regulates the release of eggs. The women then gave blood samples so researchers could measure the levels of the medication in the body.

The authors of the study found that the medication cleared from obese women's systems faster than normal-weight women's.

These authors suggested that obese women may experience premature ovulation due to the altered effectiveness of the medication.

"If you are obese, talk to your doctor about your IVF protocol."

Nanette Santoro, MD, of the Divisions of Reproductive Endocrinology and Infertility at the University of Colorado, led this study.

In vitro fertilization, or IVF, is a type of reproductive technology that is used to help women become pregnant.

Women undergoing IVF have their eggs harvested. IVF technicians then mix sperm with the egg outside the body and transfer embryos back into the uterus.

Women who choose IVF must take certain hormones and medications to help their body produce enough eggs and discharge them at the right time.

This study looked at whether IVF medications work for obese women as well as they do for women at a normal weight.

The researchers recruited 10 obese women and 10 normal-weight women to participate in their study.

Each woman was given a normal dose of cetrorelix, a medication used to control the timing of ovulation. Cetrorelix inhibits the luteinizing hormone, a natural substance in the body that causes eggs to be released.

Each of the participants gave blood samples every 10 minutes for six hours.

The researchers used the blood samples to see how much cetrorelix the women had absorbed and how much luteinizing hormone was released.

They found that half of the obese women had a 50 percent or greater increase in luteinizing hormone from the start of the study over the 14-hour period after dosage.

None of the normal-weight participants experienced an increase in the levels of the hormone.

Additionally, cetrorelix cleared out of the obese women's bodies faster than the normal-weight women's bodies.

The researchers concluded that the typical dose of the IVF medication may not be as effective for obese women as it is for women with a normal weight.

The authors of this study acknowledged that their research had limitations, primarily a small sample size.

These authors suggested that IVF protocol for obese women should be investigated further.

This study was published on March 20 in the Journal of Clinical Endocrinology and Metabolism.

The research was supported by the National Institutes of Health, the Center for the Study of Reproductive Biology and the University of Colorado Cancer Center. Some of the researchers reported financial ties to pharmaceutical companies.

Review Date: 
March 21, 2014
Last Updated:
March 23, 2014