The comparison of pregnancy outcomes in fresh and frozen embryo transfer: A cross-sectional study

Background: The benefits of frozen embryo transfer (FET) vs. fresh embryo transfer for in vitro fertilization (IVF) have been discussed in previous studies. Objective: To determine and compare the pregnancy outcomes following FET and frozen embryos transfer in women who underwent assisted reproductive techniques. Materials and Methods: In this cross-sectional study, ۲۳۳ women candidates for IVF/intra cytoplasmic sperm injection who referred to the Kamali Training Medical Center, Karaj, Iran during ۲۰۱۹-۲۰۲۰ were evaluated in ۲ groups of fresh (n = ۱۲۷) and frozen (n = ۱۰۶) embryo transfers. The rates of pregnancy outcomes including chemical and clinical pregnancy, live birth, preeclampsia, ectopic pregnancy, still birth, and pregnancy loss were compared between groups in ۳ age subgroups (< ۲۵, ۲۵-۳۵, and ۳۵-۴۰ yr old). Results: No significant difference in terms of chemical and clinical pregnancy and live birth rates were observed between groups in women aged < ۲۵ yr. Chemical and clinical pregnancy and live birth rates were significantly higher in the FET group compared to fresh group in ۲۵-۳۵-yr-old women (p = ۰.۰۱, p = ۰.۰۳, and p = ۰.۰۱, respectively). In ۳۵-۴۰-yr-old women, no significant differences were observed in terms of chemical and clinical pregnancy rates, but live birth rate was found to be significantly higher in the FET group (p = ۰.۰۲). The pregnancy loss was lower in the FET group (p = ۰.۰۳۸). Conclusion: In conclusion, the FET method in women aged ۲۵-۳۵ yr significantly increases the chance of successful IVF/intra cytoplasmic sperm injection.