A Randomised Controlled Trial To Assess The Role Of Routine Third Trimester Ultrasound In Low Risk Pregnancy On Antenatal Interventions And Perinatal Outcome

Abstract

Background: Although 80% of pregnancies are considered low risk antenatally, perinatal mortality is higher in them due to low index of clinical suspicion and lesser sensitivity of clinical assessment to detect high risk fetuses. Third trimester ultrasound can be used to detect conditions such as abnormalities in fetal growth, liquor & late onset fetal anomalies. This followed by appropriate antenatal interventions lead to improvement in perinatal outcome. Objective: To assess the role of routine third trimester ultrasound in low risk pregnancy on antenatal interventions and perinatal outcome. Methodology: Design: Randomized controlled study. Setting: KLES Dr. Prabhakar Kore Hospital and Medical Research Center, Belgaum. Subjects: A total of 290 low risk pregnant women between 34- 37 weeks attending antenatal clinics and fulfilling inclusion criteria were allotted using Computer generated randomization numbers into study and control groups. Intervention: In study group, third trimester ultrasound was performed to assess fetal growth, AFI, malpresentations, and late onset fetal anomalies. In control group, no routine ultrasound was performed, unless indicated by clinical suspicion during subsequent visits. High risk fetuses identified were managed as per the standard protocol. All women were followed to assess antenatal interventions, Intrapartum events and perinatal outcome. IV Results: Detection of high risk fetuses antenatally in study and control group was 14.48% and 2.07% respectively. This difference was statistically significant. ( p value-0.0001) . Rates of antenatal interventions among study and control was 24.8% & 4.44% respectively. Prevalence of SGA fetuses among study and control was 6.9% V/s 11.03% respectively. This difference was not statistically significant. ( p value- 0.253) There was no statistical difference in adverse intrapartum events, Caesarean section rate for non reassuring CTG, low APGAR score and NICU admissions among study and controls. Conclusion: Routine third trimester ultrasound is a logical solution for detection of high risk fetuses in low risk pregnancies which would otherwise be missed by clinical examination. However this leads to an increase in antenatal interventions without significantly influencing the perinatal outcome.