Investigating the Association between Placental Site in the Second Trimester of Pregnancy and Pregnancy Outcomes in Mother and Infant: A Retrospective Study

Background: The location of placenta is essential for the proper growth of fetus. This study was conducted to assess the relationship between placental location and perinatal and neonatal outcomes. Materials and Methods: The present retrospective cohort study was carried out on ۱۰۰۰ pregnant women who had delivered in Baqiyatallah Hospital, Tehran, Iran, during ۲۰۱۶-۲۰۱۸. We used a researcher-made questionnaire for collection of clinical and demographic information of patients from their medical records. All women had undergone a detailed ultrasound and Doppler examination at ۲۰–۲۳ weeks. We classified placenta position to four types: Lateral, Posterior, Anterior and Fundal. The data were analyzed using SPSS software version ۲۰.۰. Results: Placental site location in ۴۴%, ۴۲.۱%, ۸.۲% and ۵.۷% of cases were anterior, posterior, lateral and fundal, respectively. The mean birth weight in subjects with lateral and posterior placental site location were ۲۹۹۹.۳±۶۴۳.۹, and ۳۲۶۹.۷±۱۷۷۶.۹ gr as lowest and highest, respectively (p <۰.۰۰۱). Among the newborns in lateral group, ۴.۸۸% of them were pre-term, which was significantly higher than other groups (P=۰.۰۳۵). The rate of IUGR birth in lateral group was ۴.۸۸% which was higher than other groups (P=۰.۰۲۳). Also, among perinatal outcomes the rate of twin pregnancy was higher in lateral group, while the percentage of female birth in this group was lower than other groups (p <۰.۰۰۱). Conclusion: Lateral placental locations are associated with a number of adverse pregnancy, delivery and infant outcomes. Placental implantation and location at ۱۴ to ۲۴ weeks can be used in the evaluation of pregnancies. In other words, knowing the placenta location can help obstetricians and gynecologists in the better diagnosis of pregnancies at higher risk of complications.