Comparison of Placental and Birth Weight Ratios in Term Neonates, Neonates with Low Apgar Score, and Stillbirths in Asian Indian Population: A Retrospective Observational Study

Introduction: Unanticipated stillbirth or a low Apgar score baby at term gestation is an adverse outcome that is difficult to communicate to parents. Such conditions can be partly attributed to placental factors, indicated by low placental weight and a mismatch in the Birth Weight to Placental Weight (BW/PW) ratio. India has the largest burden of stillbirths; however, there is a lack of data from India on BW/PW ratios for stillbirths. Aim: To determine if there are significant differences in PW between normal live births, live births with low Apgar scores and stillbirths at term using local population centiles. Materials and Methods: A retrospective observational study was conducted using data retrieved from electronic medical records from January 2019 to December 2022 at the obstetrics department of Fernandez Hospital, a private tertiary referral perinatal institute with an Asian Indian population. All singleton term births were included after excluding multifoetal births, medical disorders and placental pathologies. The population was divided into three groups: newborns with normal Apgar scores, those with low Apgar scores and stillborn infants. STATA v14.0 (College Station, TX, USA) was used for statistical analysis to assess differences between the groups, with newborns with normal Apgar scores as the reference group. Results: There were 35,576 births during the study period, with 18,143 singleton term pregnancies, including 17,986 term normal Apgar births, 110 low Apgar births (0.36%), and 47 stillbirths (1.37 per 1,000). The mean BW, PW (p-value<0.001), and the proportion with PW <10th centile (p-value<0.001) differed significantly between the three groups. The BW/PW ratio was >90th centile in 10 stillbirths (21.74%), reflecting a mismatch in foetal and placental weight. Conclusion: Lower PW and higher BW/PW ratio centiles in term stillbirths validate their use as measures of placental function in evaluating all term adverse outcomes.