A study taking place at the University of Vermont and six other centers in the National Institute of Child Health and Human Development's Reproductive Medicine Network is examining a new treatment hoped to help achieve the best outcome for mother and baby — a "singleton" birth, meaning just one baby.
About 7.3 million women between the ages of 15 and 44 are classified as having an "impaired ability to have children," according to the Centers for Disease Control. Study investigator Peter Casson, M.D., UVM professor of obstetrics, gynecology and reproductive sciences and director of reproductive endocrinology and infertility at UVM/Fletcher Allen, says the study focuses on one of the most common causes of infertility — Polycystic Ovary Syndrome or PCOS. Often associated with weight and diabetes, the condition is yet another consequence of the country's obesity epidemic.
In this randomized, double-blind study, participants will receive either the new drug — called letrozole — or the currently used treatment clomiphene citrate. Secondary aims of the study are to determine whether letrozole offers patients an improved quality of life and is more cost-effective than clomiphene.
In PCOS, excess fat production increases estrogen production, thereby blocking inappropriate estrogen signaling to the pituitary gland and causing infertility. Letrozole, a drug also used to lower recurrence risk in certain breast cancer patients, is classified as an aromatase inhibitor. Aromatase is an enzyme that converts the hormone androgen into estrogen. In an aromatase inhibitor, this conversion is blocked. Clomiphene is a selective estrogen receptor modulator, which essentially tricks the brain into thinking there are low levels of estrogen, thereby stimulating egg production in the ovaries.
"Clomiphene has about a five percent risk of multiple pregnancies and is very expensive," explains Casson. "Letrozole works differently than clomiphene, in that it produces more of a physiological 'kick-start' of the ovaries. Given the prevalence of PCOS, which is often accompanied by other health issues, we hope our hypothesis is correct that letrozole could have a significant effect on the singleton birth rate and outcomes in women with this condition."
The UVM site expects to enroll between 100 and 200 participants in this study, which will run through 2012. Participants must be females between the ages of 18 and 40 years old with a diagnosis of PCOS. For more information on the trial, contact Adrienne Schonberg at 802-656-7505 or adrienne.schonberg@uvm.edu .