Role of Amniotic Fluid to Umbilical Cerebral Ratio for Anticipation of Perinatal Outcome in Appropriate for Gestational Age Foetuses at Term: A Prospective Observational Study

Introduction: The role of amniotic fluid in embryonic development is crucial. Amniotic Fluid Volume (AFV) is maintained by physiological processes that vary with gestational age. Either oligohydramnios or polyhydramnios, a variation from the normal volume, may be related to maternal and foetal problems. Hence, considering the importance of amniotic fluid, combining Doppler with the amniotic fluid deepest vertical pocket as a ratio, for foetal wellbeing assessment might be helpful. Aim: To study the role of Amniotic Fluid to Umbilical Cerebral Ratio (AUCR) in prediction of perinatal outcome in Appropriate for Gestational Age (AGA) foetuses at term. Materials and Methods: A prospective observational study was conducted in the Department of Obstetrics and Gynaecology, King George’s Medical University, Lucknow, Uttar Pradesh, India from May 2021 to May 2022. Foetal Doppler ultrasound examinations, which included Umbilical Artery (UA) Doppler (systolic diastolic ratio (S/D), Pulsatility Index (PI), Resistive Index (RI)), and Middle Cerebral Artery (MCA) Doppler (S/D, PI, RI). AUCR was calculated as the ratio of Single Deepest Pocket (SDP) to Umbilical Cerebral Ratio (UCR= UAPI/MCAPI- UA PI/ MC PI). Beyond this Cerebroplacental Ratio (CPR=MCAPI/ UAPI- MC PI/UA PI was done. Caesarean Delivery (CD) and Operative Vaginal Delivery (OVD) due to foetal distress had been collectively termed as “OI due to foetal distress”. Also, Apgar scores and neonatal unit admissions were noted. Results: Total 112 term AGA pregnancies were followed in the present study. The age range was 18–40 years with a mean age of 26.34 years and the mean Body Mass Index (BMI) was 24.88 kg/ m2 . Out of 112 term pregnancies, 56 foetuses had foetal distress, of which five had Operative Vaginal Delivery (OVD) by outlet forceps and 51 patients had Lower Segment Caesarean Section (LSCS). Ten newborns needed Neonatal Intensive Care Unit (NICU) a admission. For predicting operative intervention (adverse perinatal outcome), the Cerebroplacental Ratio (CPR) demonstrated the highest diagnostic accuracy with an AUC of 0.801 (p-value<0.001), followed by MCA PI (AUC 0.781) and AUCR (AUC 0.72). Conclusion: Inclusion of amniotic fluid in the ratio in the form of AUCR has moderate predictive ability for the prediction of poor outcome in AGA foetuses.