Management of isolated abnormal amniotic fluid volume in pregnancy

Key content Amniotic fluid volume (AFV) is a vital measurement in the determination of fetal well‐being by means of ultrasound. There are many factors that determine AFV and, in many cases, complications affecting the fetus may manifest through change in its value. Isolated abnormal amniotic fluid index antenatally is relatively common, but its management remains contentious. The prevalence in the United Kingdom for isolated oligohydramnios is up to 5% of pregnancies, and isolated polyhydramnios complicates up to 2% of pregnancies. This article reviews and discusses the maternal and fetal implications of isolated oligohydramnios and polyhydramnios in the antenatal period, intrapartum and neonatal period. Learning objectives Overview of oligohydramnios and polyhydramnios and their aetiologies. Review threshold for timing of delivery and management of isolated oligohydramnios and polyhydramnios. Review of fetal and neonatal complications of oligohydramnios and polyhydramnios and their management.