Comparison of live birth rate and fetal outcomes between fresh embryo and frozen-thawed embryo transfers: a prospective study

BACKGROUND: The study aimed to compare the pregnancy, prenatal, and postnatal outcomes between fresh and frozen embryo transfer (ET) in intracytoplasmic sperm injection (ICSI) cycles at Al-Zahra Referral Women's Hospital in northwest Iran. METHODS: A prospective study was conducted among all infertile women (N = 469) who underwent embryo transfer between 2018 and 23 at Al-Zahra referral infertility center. Patients in cycles with fresh embryo transfer and patients for whom frozen embryos were transferred were compared in terms of live birth rate and fetal outcomes. Multiple logistic regression analysis was used to estimate adjusted odds ratios (AORs) with 95% confidence intervals (CIs). RESULTS: The majority of the participants were primary infertility 83.3%. The rate of chemical and clinical pregnancy was (21.8% vs. 17.2%) and (19% vs. 13.4%) in the fresh embryo and the frozen embryo transfers, respectively. Likewise, the rate of live births was (14.1% vs. 9.1%), respectively. The number of retrieved oocytes was significantly higher in frozen ET compared to fresh ET (P = 0.001). In the final analysis, after adjusting for potential confounders, no significant associations were found for clinical pregnancy (AOR = 1.51; 95% CI: 0.90-2.5; P = 0.125) and chemical pregnancy (AOR = 1.31; 95% CI: 0.81-2.3; P = 0.238) rates between fresh and frozen ETs. Similarly, there were no significant differences in live birth rate (AOR = 1.6; 95% CI: 0.54-12.4), preterm birth (AOR = 0.62; 95% CI: 0.33-5.5), and primary infertility (AOR = 0.73; 95% CI: 0.34-1.6) between fresh and frozen ETs. The incidence of multiple pregnancies and spontaneous abortion was (5% vs. 13.8%) and (22.2% vs. 30.2%) in the fresh embryo and frozen embryo groups, respectively. CONCLUSION: No significant differences in perinatal and postnatal outcomes were found between fresh and frozen embryo transfers.