Oligohydramnios and associated fetal complications

Abstract

During intrauterine life the fetus is bathed in amniotic fluid which provides a low resistance space for free movement and a buffer against external trauma. This fluid is produced in early pregnancy largely as a maternal dialysate, then as a fetal transudate. Fetal urine is the most important source of amniotic fluid after 16 weeks gestation. The control of amniotic fluid is complex and poorly understood; it arises from secondary partitioning of water within the fetoplacental extracellular space and reflects fetal fluid balance.