Elective cryopreservation of all embryos with subsequent cryothaw embryo transfer in patients at risk for ovarian hyperstimulation syndrome reduces the risk of adverse obstetric outcomes: a preliminary study

Objective To test the hypothesis that patients who undergo elective cryopreservation of all embryos, due to risk of ovarian hyperstimulation syndrome and elevated peak serum estradiol (E2 ), previously defined as level >3,450 pg/mL (90th percentile) during in vitro fertilization (IVF), will be less likely to have small for gestational age (SGA) infants and preeclampsia as compared with patients with elevated peak serum E2 who undergo fresh embryo transfer (ET). Design Cohort study. Setting Tertiary care academic medical center. Patient(s) Twenty women who underwent elective cryopreservation of all embryos with subsequent cryothaw ET and 32 similar women with elevated peak E2 during controlled ovarian hyperstimulation for IVF who underwent a fresh ET. Intervention(s) None. Main Outcome Measure(s) Prevalence of SGA infants and development of preeclampsia in patients with cryothaw ET or fresh ET in the setting of elevated peak E2. Result(s) After adjusting for confounders (body mass index, antral follicle count, peak serum E2 level) using forward stepwise logistic regression, the patients who elected cryopreservation of all embryos and subsequent cryothaw ET were statistically significantly less likely to deliver SGA infants as compared with the patients who had fresh ET in the setting of elevated peak E2 . In the entire cohort, a total of seven women had preeclampsia, all of whom had had fresh ET in the setting of elevated peak serum E2 : 7 (21.9%) in the fresh ET group versus 0 women in the elective cryopreservation group. Conclusion(s) This preliminary study suggests that elective cryopreservation of all embryos in patients with elevated peak serum E2 for subsequent cryothaw ET in cycles with a better physiologic hormonal milieu may reduce the odds of SGA and preeclampsia in IVF singleton deliveries.