In oligohydramnios there is reduced amniotic fluid. Definitions vary but include less than 500ml at 32-36 weeks and an amniotic fluid index (AFI) < 5th percentile.

Causes

• premature rupture of membranes
• Potter sequence
  • bilateral renal agenesis + pulmonary hypoplasia
• intrauterine growth restriction
• post-term gestation
• pre-eclampsia