Clinical outcomes of fresh versus frozen embryo transfers and its influence on mid-trimester miscarriage and fetal birth weight: A retrospective study

Abstract

Aim: The aim of the study was to compare the clinical outcomes of fresh and frozen embryo transfer (FET) in women undergoing assisted reproductive technology and its influence on mid-trimester miscarriage and fetal birth weight. Materials and Methods: The study was conducted between June 2016 and June 2019. The study group comprised 778 cycles, of women, who were undertaken in this retrospective analysis of in vitro fertilization cycles who underwent fresh and FET. These women were randomly divided into two groups, fresh embryo transfers (n = 410) and FETs (n = 368). Both groups were compared with their respective outcome measures such as the clinical pregnancy rates (CPRs), miscarriage rates, multiple pregnancy rates as well as live births and birth weights. Results: The mean age of the participants in fresh and FET groups was 31.13 ± 4.39 and 31.45 ± 4.25, respectively. There were statistically significant differences with respect to clinical pregnancy (P = 0.002) between the groups. Fetal miscarriage rates (30.14% vs. 23.53%) as well as birth weights were not statistically significant (P = 0.164) between fresh versus FET. The results clinically signified that the FET gives a lower miscarriage rate and higher CPRs while not affecting the average fetal birth weight. Conclusion: Adjusting the baseline characteristics and exclusion criteria of participants, women undergoing FET were associated with better clinical outcomes than women undergoing fresh ET cycles Contrary to existing literature, our incidence of neonatal morbidities, or large birth weights were not increased and fetal macrosomia did not occur. Gaining debates on the advantage of frozen over fresh transfers and its effects on obstetric and neonatal outcomes may require a large multicenter pooling of data and analyses.