The Usefulness of Ultrasound Assessment of Amniotic Fluid in Predicting Adverse Outcome in Prolonged Pregnancy: A Prospective Blinded Observational Study

Abstract

Abstract Objective To determine whether a single ultrasound scan at or beyond 40 weeks of gestation to detect a single deepest pool of amniotic fluid Design A prospective double blind cohort study. Setting A university teaching hospital delivering approximately 6000 women annually. Population One thousand and five hundred and eighty-four pregnant women at or beyond 40 weeks of gestation. Methods Ultrasound assessment of liquor to detect the single deepest pool of amniotic fluid and derive the AFI at or after 40 weeks of gestation. Main outcome measures Perinatal death, meconium aspiration, birth asphyxia, intervention in labour for fetal distress, a cord arterial pH Results An AFI Conclusions The AFI is superior to a measure of the single deepest pool as an assessment of the fetus at or after 40 weeks but has a poor sensitivity for adverse pregnancy outcome. Routine use is likely to lead to increased obstetric intervention without improvement in perinatal outcomes.