Risk factors for placenta previa among pregnant women of Kyiv, Ukraine: a retrospective cohort study

Placenta previa is a significant obstetric problem with elevated morbidity and mortality rates for both mother and fetus. The risks associated with placenta previa underscore the necessity for comprehensive treatment and timely intervention to mitigate adverse outcomes. Purpose - to conduct a retrospective analysis of the impact of obstetric-gynecological factors on the prediction of placenta previa occurrence and its influence on perinatal outcomes. Materials and methods. A retrospective cohort study was conducted on cases of placenta previa between 2018 and 2022. The study included 22491 deliveries, of which 65 (0.29%) cases were registered as placenta previa. Data from delivery records of 374 patients without placenta previa were used for comparison. The following variables were evaluated for all patients: maternal age, characteristics of the menstrual cycle, gravidity, parity, history of cesarean sections, gestational age at delivery, method of delivery, blood loss during delivery, length of postpartum hospitalization, birth weight, gender of the newborn, Apgar scores at 1 and 5 minutes. Gynecological intervention histories, including curettage/hysteroscopy, laparoscopy, and cervical treatment, as well as obstetric pathologies, such as cesarean section, ectopic pregnancy, instrumental abortions, missed pregnancies, and assisted reproductive technologies in the last pregnancy, were examined. Results. Multifactorial analysis revealed four significant risk factors. The risk of placenta previa was found to increase with advanced maternal age (p<0.001), OR=1.14 (95% CI 1.07-1.20), and the presence of previous cesarean sections (p<0.001), OR=5.51 (95% CI 2.73-11.1), while a history of previous deliveries reduced the risk (p<0.001), OR=0.24 (95% CI 0.15-0.40). Instrumental abortions increased the risk of placenta previa (p=0.001), OR=2.14 (95% CI 1.20-3.81). Newborns in the placenta previa group had lower Apgar scores at 1 and 5 minutes and lower birth weight. Conclusions. The obtained results emphasize the importance of considering risk factors in assessing placenta previa occurrence during antenatal monitoring and can contribute to improving obstetric and perinatal care for women. However, the morphological and functional basis of placenta previa remains unknown and requires further study. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of participating institution. No conflict of interests was declared by the authors.