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

Abstract

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 (E(2)), 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 E(2) who undergo fresh embryo transfer (ET). Cohort study. Tertiary care academic medical center. Twenty women who underwent elective cryopreservation of all embryos with subsequent cryothaw ET and 32 similar women with elevated peak E(2) during controlled ovarian hyperstimulation for IVF who underwent a fresh ET. None. Prevalence of SGA infants and development of preeclampsia in patients with cryothaw ET or fresh ET in the setting of elevated peak E(2). After adjusting for confounders (body mass index, antral follicle count, peak serum E(2) 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 E(2). 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 E(2): 7 (21.9%) in the fresh ET group versus 0 women in the elective cryopreservation group. This preliminary study suggests that elective cryopreservation of all embryos in patients with elevated peak serum E(2) for subsequent cryothaw ET in cycles with a better physiologic hormonal milieu may reduce the odds of SGA and preeclampsia in IVF singleton deliveries.