Oligohydramnios is defined as a reduction in amniotic fluid volume below 500 ml, and in rare cases there may be a complete absence of fluid known as anhydramnios. It occurs in approximately 1 in 750 pregnancies and can be caused by placental insufficiency, urinary tract malformations in the fetus, or post-term pregnancy. Ultrasound is used to diagnose oligohydramnios and identify any fetal anomalies, growth problems, or the fetal presentation. Complications include pulmonary hypoplasia if the fluid is needed for lung development, abnormal fetal development due to compression, and abnormal fetal presentations. Management depends on if it occurs post-term, in which case

1. OLIGOHYDRAMNIOSwww.freelivedoctor.com

2. DefinitionReduction of amniotic fluid volume below 500 ml. Anhydramnios is complete absence of amniotic fluid which is very rare.Incidence1:750.www.freelivedoctor.com

3. Aetiologya.Placental insufficiency: as in severe pre-eclampsia and post-term pregnancy.b. Urinary tract malformations: as renal agenesis (detected by empty foetal bladder on serial ultrasonic scanning) and obstruction of the urinary tract.www.freelivedoctor.com

4. Clinical Picturea. Uterus is small for date.b. The foetus is in hyperflexed attitude and breech presentation is common.www.freelivedoctor.com

5. Investigations Ultrasound: shows small (<1x1cm) amniotic fluid locules. It is important to exclude congenital anomalies, growth retardation and identifies foetal presentation.www.freelivedoctor.com

6. Complicationsa. Pulmonary hypoplasia: as the amniotic fluid is essential for lung distension.b. Abnormal foetal development: due to compression of uterine wall and adherent foetal parts. c. Abnormal presentations.www.freelivedoctor.com

7. ManagementIn post-term: Termination of pregnancy is indicated.b.Duringlabour: Observe for foetal distress as it is more common, if occurs do immediate vaginal or abdominal delivery according to the circumstances.www.freelivedoctor.com