Can we abandon routine evaluation of serum estradiol levels during controlled ovarian hyperstimulation for assisted reproduction?

Objective: To assess whether abandoning measurement of serum estradiol (E₂) and spacing ultrasound evaluations at greater intervals had an effect on the results of assisted reproduction technology (ART). Design: A retrospective comparison of two consecutive periods. Setting: Division of Assisted Reproduction Technology, Department of Obstetrics and Gynecology, Ha'Emek Medical Center, Afula, Israel. Patient(s): One thousand nine hundred and eighty-five controlled ovarian hyperstimulation (COH) cycles for ART were initiated during the years 1996 to 1999. Intervention(s): During the first 2 years an intensive follow-up protocol was used that included E₂ blood levels measurements. In the next 2 years a less intensive protocol was adopted that did not use E₂ measurements. Main Outcome Measure(s): ART results and the rate of ovarian hyperstimulation syndrome (OHSS). Result(s): The patients' background characteristics did not differ between the two periods. The cancellation rate was not different (9.8% vs. 7.2%). There was no difference in the duration of stimulation or the amount of gonadotropins used. The number of oocytes retrieved (12.1 ± 9.3 vs. 9.6 ± 6.3), fertilization rates (74% vs. 75%), and clinical pregnancy rates (26.2% vs. 27.9%) did not differ. The incidence of severe ovarian hyperstimulation syndrome was not significantly different between the two periods. Conclusion(s): Controlled ovarian hyperstimulation for ART can be done reliably without routine, serial serum E₂ measurements without compromising the treatment results.