Role of midtrimester localization of the placenta in predicting pregnancy outcome

The localization of the placenta by ultrasound in the second trimester has been hypothesized to have an impact on the pregnancy, in terms of antenatal, intrapartum and postnatal outcome. Objective: To evaluate the role of placental location in predicting the pregnancy outcome. Materials and methods: It was a prospective observational study conducted between September 2011 and March 2013 at a tertiary care hospital. Placental location, as determined by midtrimester ultrasound in 620 antenatal women, was divided into five groups-anterior, posterior, fundal, lateral and low lying placenta-depending on where > 75% of the placental mass was located. Outcome variables, such as antenatal complications, intrapartum events and neonatal outcome in these women were studied. Results: Out of 620 women, 274 (44.1%) had anterior, 169 (27.2%) had posterior, 98 (15.8%) had fundal, 61 (9.8%) had lateral placentae and 18 (2.9%) had placenta previa as per the last scan done at 28 weeks. Pre-eclampsia (27.9%) and antepartum hemorrhage (19.7%) were more common in lateral placenta whereas term prelabor rupture of membranes (11.2%) was more common in fundal placenta and these findings were statistically significant. The incidence of intrauterine growth restriction (IUGR) was also found to be higher in patients with lateral (16.4%) and posteriorly (16%) implanted placenta although there was no statistically significant association. Conclusion: Among the various placental sites of implantation, lateral location of the placenta is associated with adverse antenatal outcomes like pre-eclampsia, antepartum hemorrhage and IUGR.