|Classification and external resources|
The common clinical features are smaller symphysiofundal height, fetal malpresentation, undue prominence of fetal parts and reduced amount of amniotic fluid.
The cause is not known but is often associated with some:
- fetal chromosomal anomolies
- intra uterine infections
- Drugs; PG inhibitors, ACE inhibitors
- renal agenesis or obstruction of the urinary tract (posterior urethral valve in male fetus)of the fetus preventing micturation
- IUGR associated with placental insufficiency
- amnion nodosum; failure of secretion by the cells of the amnion covering the placenta
- postmaturity (dysmaturity)
- uterine size is much smaller than the period of amenorrhoea
- less fetal movements,
- the uterus "full of fetus" because of scanty liquor,
- evidences of intra uterine growth retardation of the fetus,
- sonographic diagnosis is made when largest liquor pool is less than 2 cm,
- visualization of normal filling and emptying of fetal bladder essentially rule out urinary tract abnormality,
- Oligohydramnios with fetal symmetric growth retardation is associated with increased chromosomal abnormality.
Complications may include cord compression, musculoskeletal abnormalities such as facial distortion and clubfoot, pulmonary hypoplasia and intrauterine growth restriction. Amnion nodosum is frequently also present (nodules on the fetal surface of the amnion).
Potter syndrome is a condition caused by oligohydramnios. Affected fetuses develop pulmonary hypoplasia, limb deformities, and characteristic facies. Bilateral agenesis of the fetal kidneys is the most common cause due to the lack of fetal urine.
A Cochrane Review concluded that "simple maternal hydration appears to increase amniotic fluid volume and may be beneficial in the management of oligohydramnios and prevention of oligohydramnios during labour or prior to external cephalic version."
In severe cases oligohydramnios may be treated with amnioinfusion during labor to prevent umbilical cord compression. There is uncertainty about the procedure's safety and efficacy, and it is recommended that it should only be performed in centres specialising in invasive fetal medicine and in the context of a multidisciplinary team.
- Adeniran AJ, Stanek J, (2007). "Amnion nodosum revisited: clinicopathologic and placental correlations". Arch Pathol Lab Med 131 (12): 1829–33. doi:10.1043/1543-2165(2007)131[1829:ANRCAP]2.0.CO;2. PMID 18081444.
- Johnson JM, Chauhan SP, Ennen CS, Niederhauser A, Magann EF (2007). "A comparison of 3 criteria of oligohydramnios in identifying peripartum complications: a secondary analysis". Am. J. Obstet. Gynecol. 197 (2): 207.e1–7; discussion 207.e7–8. doi:10.1016/j.ajog.2007.04.048. PMID 17689653.
- Elsandabesee D, Majumdar S, Sinha S (2007). "Obstetricians' attitudes towards 'isolated' oligohydramnios at term". Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology 27 (6): 574–6. doi:10.1080/01443610701469669. PMID 17896253.
- Hofmeyr GJ, Gülmezoglu AM (2000). Novikova, Natalia, ed. "Maternal hydration for increasing amniotic fluid volume in oligohydramnios and normal amniotic fluid volume". Cochrane Database of Systematic Reviews (Online) (2): CD000134. doi:10.1002/14651858.CD000134. PMID 10796151.
- Oligohydramnios at the National Institute for Health and Clinical Excellence. Based on the overview Therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour) in 2006
- Morris, R. K.; Malin, G. L.; Quinlan-Jones, E.; Middleton, L. J.; Hemming, K.; Burke, D.; Daniels, J. P.; Khan, K. S.; Deeks, J.; Kilby, M. D. (2013). "Percutaneous vesicoamniotic shunting versus conservative management for fetal lower urinary tract obstruction (PLUTO): A randomised trial". The Lancet 382 (9903): 1496. doi:10.1016/S0140-6736(13)60992-7.