Evaluation of Placental Weight Ratio in Preterm Births and Small for Gestation Age Babies in Preeclampsia in Sikkimese Population

Background: Studies have established placental weight ratio (PWR) as a relevant marker of fetal uteroplacental function which reflects whether the fetal and placental growth is proportionate. It decreases across gestation as the placental growth slows and fetal growth accelerates. Preeclampsia and preterm birth are both risk factors of small for gestational age (SGA) off springs with the smaller placenta. The PWR is elevated in both these conditions which share a common pathophysiology. Aim: The study aims to determine if PWR is a reliable indicator of placental function and fetal growth and to evaluate the PWR by gestational age in preterm births in preeclampsia in Sikkimese population. Methods: A total of 150 placentae were analyzed, out of which 100 were from normotensive mothers and 50 from pre-eclamptic mothers. Data analysis was done using Statistical Package of Social Sciences 17. Student’s t-test and Fisher’s Chi-square test. P < 0.05 was considered to be statistically significant. Results: Significantly, higher PWR was observed in pre-eclamptic pregnancies (0.001) and in both preterm (0.009) and term (0.048) births. The elevated ratio was observed only in SGA off springs (0.037) of pre-eclamptic mothers and not in normotensive mothers. Decreasing PWR across gestation was documented only in pre-eclamptic patients. The mean birth weight (0.004) and placental weight (0.0001) were significantly reduced in pre-eclamptic pregnancies while the PWR was elevated. The peak placental growth was delayed by several weeks in preeclampsia. No significant difference between preterm and term off springs of cohorts or controls was observed. Conclusion: Preeclampsia is a confounding variable in SGA leading to raised PWR and is a reliable indicator of pregnancy complications. The influence of gestational age on this ratio and uteroplacental function could not be established. The PWR is not a relevant marker of fetal growth as it is not raised in all SGA off springs.