Signs and symptoms
The common clinical features are smaller symphysio-fundal height, fetal malpresentation, undue prominence of fetal parts and reduced amount of amniotic fluid.
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.
The cause is not known but is often associated with some:
- fetal chromosomal anomalies like triploidy
- intra uterine infections
- premature rupture of membrane
- drugs; COX inhibitors like indomethacin, ACE inhibitors
- renal agenesis or obstruction of the urinary tract of the fetus preventing micturition such as posterior urethral valves in males
- intrauterine growth restriction (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
- fewer fetal movements,
- the uterus "full of fetus" because of scanty liquid,
- malpresentation (breech)
- evidences of IUGR of the fetus,
- sonographic diagnosis is made when largest liquid 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.
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:10.5858/2007-131-1829-ANRCAP. 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. 27 (6): 574–6. doi:10.1080/01443610701469669. PMID 17896253. S2CID 39603642.
- Hofmeyr, G. J.; Gülmezoglu, A. M. (2002). "Maternal hydration for increasing amniotic fluid volume in oligohydramnios and normal amniotic fluid volume". The Cochrane Database of Systematic Reviews (1): CD000134. doi:10.1002/14651858.CD000134. ISSN 1469-493X. PMC 7045461. PMID 11869566.
- Oligohydramnios Archived 2016-09-20 at the Wayback Machine at the National Institute for Health and Clinical Excellence. Based on the overview Therapeutic amnioinfusion for oligohydramnios during pregnancy (excluding labour) Archived 2013-02-18 at the Wayback Machine 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): 1496–1506. doi:10.1016/S0140-6736(13)60992-7. PMC 3898962. PMID 23953766.