Effect of grade 3 placenta <36 weeks of pregnancy on perinatal outcomes

The aim of this study was to assess whether the presence of grade 3 placenta <36 weeks of pregnancy is associated with adverse perinatal outcomes.

Retrospective cohort study in which patients were separated into the following three groups: 1) grade 3 placenta <36 weeks, 2) grade 3 placenta >36 weeks, 3) no occurrence of grade 3 placenta throughout pregnancy. The χ² and general linear model tests were used to compare adverse perinatal outcomes. Binary logistic regression model was used to estimate the odds ratio (OR) for adverse perinatal outcomes. Receiver operating characteristic (ROC) curve was used to determine the cut-off of the middle cerebral artery Pulsatility Index (MCA PI) in the detection of births <37 weeks in grade 3 placentas <36 weeks.

Significant association was observed between grade 3 placenta <36 weeks and birth <37 weeks (P<0.001), birth weight <10^th percentile (P=0.001), 5-min Apgar Score <7 (P=0.014), admission to neonatal intensive care unit (P<0.001), and fetal death (P=0.002). Grade 3 placenta <36 weeks was significant predictor for birth <37 weeks (OR: 2.6; 95% CI: 1.74-3.92), pre-eclampsia (OR: 1.8; 95% CI: 1.02-3.27), birth weight <10^th percentile (OR: 2.1; 95% CI: 1.39-3.10), fetal death (OR: 5.6; 95% CI: 1.65-18.78), and composite perinatal outcomes (OR: 2.2; 95% CI: 1.51-3.17). The MCA PI showed an area under ROC curve of 0.641 (95% CI: 0.546-0.728) in the detection of births <37 weeks.

Grade 3 placenta <36 weeks was associated with a higher prevalence of adverse perinatal outcomes.