A GnRH agonist and exogenous hormone stimulation protocol has a higher live-birth rate than a natural endogenous hormone protocol for frozen-thawed blastocyst-stage embryo transfer cycles: an analysis of 1391 cycles

ObjectiveTo compare embryo and birth data in cryopreserved-thawed blastocyst-stage ET cycles between natural endogenous hormone cycles and exogenous hormone stimulation cycles.DesignRetrospective cohort analysis.SettingLarge academic assisted reproductive technology center.Patient(s)One thousand three hundred ninety-one patient cycles undergoing frozen-thawed blastocyst-stage ET cycles.Main Outcome Measure(s)Live-birth rate.Intervention(s)The synthetic protocol used GnRH agonist followed by estrogen and P. The natural protocol used monitoring and post-transfer P.Result(s)The patients in the two protocols had similar baseline characteristics. Multiple linear regression showed the synthetic protocol to have a higher live-birth rate (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.02–2.09). In patients having two embryos transferred, the synthetic stimulation protocol resulted in a higher live-birth rate per cycle start (32.3% vs. 20.4%; relative risk [RR], 1.58; 95% CI, 1.22–2.06). Similarly, patients with one or two embryos transferred who had additional cryopreserved blastocysts available also had a higher live-birth rate per cycle start (36.1% vs. 12.1; RR, 2.98; 95% CI, 1.16–7.63).Conclusion(s)The synthetic hormone protocol was associated with a higher live-birth rate when compared with a natural cycle protocol for frozen-thawed blastocyst-stage ET cycles. This improvement persisted when analysis was controlled for cycle cancellation. The synthetic stimulation protocol for frozen-thawed embryo cycles offers improved outcome results for patients.