Embryo transfer protocol preferences are known to influence obstetric and perinatal outcomes in IVF (in vitro fertilisation) cycle pregnancies. However, placental location in fresh embryo transfer (fET) and frozen embryo transfer (FET) has not been adequately evaluated and is an area of research. The aim of our study is to investigate the factors affecting placental location and obstetric and perinatal outcomes of pregnancies induced by an IVF cycle resulting in a singleton live birth. In our study, 329 pregnancies resulting in a singleton live birth were retrospectively evaluated between 2015 and 2021 at the Department of Gynecology and Obstetrics, University of Health Sciences Tepecik Training and Research Hospital, Assisted Reproductive Treatment Center. Placental location data were obtained from second trimester ultrasonography scans. Patients were divided into two groups according to whether the pregnancy was obtained with fET (232) or FET (97). Groups were statistically compared with respect to maternal demographics, smoking, body mass index (BMI), previous uterine surgery, cause of infertility and accompanying comorbidities. Relationships between patient and treatment-related factors, obstetric and perinatal outcomes and placental location were examined. Of the 327 patients, 232(70.9%) achieved pregnancy with fET and 97(21.1%) with FET. Age, BMI and smoking history were similar in both ET cycles. Significant difference was found in causes of infertility(p=0.001), abortion history(p=0.04), gravidity(p=0.04) and thrombophilia(p=0.007). fET cycles were associated with preterm birth(p=0.022), small for gestational age(p=0.014), premature rupture of membranes(p=0.004). FET cycles were associated with gestational hypertension(p=0.033). There was no association regarding placental location(p=0.28). There was significant correlation between the location of the placenta and the patient's history of abortion(p=0.04) and the number of embryos transferred(p=0.038). History of uterine intervention in FET cycles was associated with inferior and lateral placentation(p=0.006). An association of placental localization and preterm births(p=0.02) was found significant in fET cycles(p=0.02) and insignificant in FET cycles(p=0.82). Lower located placenta caused an 8-fold increased risk of postpartum hemorrhage(aOR=8.6) and lateral located placenta resulted a 3.5-fold increased risk of fetal growth restriction (aOR=3.54) and minor anomalies(aOR=3.61). In IVF pregnancies, patient and treatment factors influence placental location. Differences in placental location may play a role in some poor obstetric and perinatal outcomes. Placental location may affect the differential obstetric and perinatal outcomes of pregnancies obtained with fET and FET cycles. The correlation between placental location and minor abnormalities may have developed as a result of the epigenetic effects of the embryo culture process. Studies with larger patient groups are needed to determine the association between placental location and obstetric-perinatal outcomes and to use placental location to predict poor pregnancy outcomes. [ABSTRACT FROM AUTHOR]