April 6, 2000 (Baltimore) -- Women who take birth control pills to prevent their ovaries from producing an egg for a month -- a process called anovulation -- prior to in vitro fertilization (IVF) experience an enhanced rate of pregnancy, a study in the current issue of the journal Fertility and Sterility reports.
"When oral contraceptives are used to induce anovulation before IVF treatment, the second IVF cycle after anovulation seems to favor pregnancy more than the first cycle," writes Misao Fukada, MD, of the Fukada Ladies' Clinic in Ako, Japan, and the study's lead author. "Anovulation may therefore provide improved conditions for the development of a healthier [egg] with an increased pregnancy potential up to two menstrual cycles later."
Fukada and colleagues used oral contraceptives to induce anovulation in more than 30 women who had each undergone a number of unsuccessful IVF attempts. All of the women had both ovaries and had developed a pre-embryo in a previous IVF cycle, indicating that their chances for a successful pregnancy were good. The pregnancy rate per cycle in the second cycle after a period of anovulation (30%) and the first and second cycle combined after a period of anovulation (23%) were significantly higher than that before anovulation (9%).
"The present study shows that a period of anovulation enhances conception rates of IVF treatment compared with the rates obtained when continuous ovulations occur," Fukada writes. Why this occurs was not explored in this study.
Fady Sharara, MD, tells WebMD, "The utility of anovulation is well-documented. We have been using oral contraceptives to induce anovulation for about six years now in our center, although many centers don't use oral contraceptives to do this. I personally feel use of oral contraceptives is paramount, because it works to quiet down the ovaries by a different mechanism than [drugs currently used in many IVF programs]." Sharara, who was not involved in the study, is associate professor in the division of reproductive endocrinology and infertility at the University of Maryland School of Medicine in Baltimore.
- The birth control pill prevents a woman's ovaries from producing an egg, creating a state called anovulation. Japanese researchers say using the pill briefly to cause anovulation may improve conditions for pregnancy to occur through in vitro fertilization (IVF) in some women.
- The researchers gave 30 women oral contraceptives to stop egg production, after IVF had been unsuccessful. In the first two attempts at IVF after anovulation, their pregnancy rate was much higher than before they took the pill.
- An observer notes that some fertility specialists are using anovulation to improve chances of pregnancy, although IVF centers may use other drugs instead to create this state.