Received October 10, 2020
Accepted May 15, 2021

Objective: The aim of this study was to precisely investigate the pregnancy outcomes in women undergoing IVF using fresh and/or frozen embryo transfer. Methods: In this retrospective patient record study, 2872 infertile women’s files, who were candidates for IVF, were reviewed. Patients were classified into two groups, including those who underwent fresh embryo transfer (n=1628) and or frozen embryo transfer (FET) (n=1244). Results: Fertility was achieved in 313 (19.23%) and 356 (28.62%) patients, who underwent fresh ET and FET, respectively. The rates of clinical pregnancy, ongoing pregnancy, and live birth were significantly higher in the FET group than the fresh ET group. The incidence of multiple pregnancies, perinatal mortality, abortion in the first trimester, preterm delivery, and low birth weight were significantly higher among fresh ET group [38 (35.51%), 15 (14.50%), 72 (23.01%), 26 (8.30%), and 33 (10.54%), respectively] than FET group [25 (15.33%), 6 (6.87%), 63 (17.69%), 14 (3.93%), and 20 (5.61%); p<0.05]. Also, the incidence of ectopic pregnancies, abortion in the second trimester, gestational diabetes, preeclampsia, and placenta previa were higher in the fresh ET group, but not significantly so (p>0.05). Conclusion: Women who underwent IVF via FET showed more successful fertility and pregnancy outcomes compared to those who underwent IVF by fresh ET.