Oligohydramnios is a condition in pregnancy

Pregnancy

Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

 characterized by a deficiency of amniotic fluid

Amniotic fluid

Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the amniotic sac of a pregnant woman.- Development of amniotic fluid :...

. It is the opposite of polyhydramnios

Polyhydramnios

Polyhydramnios is a medical condition describing an excess of amniotic fluid in the amniotic sac. It is seen in 0.2 to 1.6% of pregnancies,,...

.

Diagnosis

Diagnosis is made by ultrasound measurement of the amniotic fluid index

Amniotic Fluid Index

Amniotic fluid index is a rough estimate of the amount of amniotic fluid and is an index for the fetal well-being. It is a part of the biophysical profile....

 (AFI) <5cm. Several different methods exist for calculating AFI, that produce different index numbers below which oligohydramnios is said to be present.

Causes

It is typically caused by fetal urinary tract abnormalities such as bilateral renal agenesis ( Potter's syndrome ), fetal polycystic kidneys, or genitourinary obstruction. Uteroplacental insufficiency is another common cause. Most of these abnormalities can also be detected by obstetric ultrasound. It may also occur simply due to dehydration

Dehydration

In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...

 of the mother, maternal use of angiotensin converting enzyme inhibitors, or without a determinable cause (idiopathic

Idiopathic

Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...

).

Complications

Complications may include cord compression, musculoskeletal abnormalities such as facial distortion and clubfoot, pulmonary hypoplasia and intrauterine growth restriction. Amnion nodosum

Amnion nodosum

Amnion nodosum are nodules on the fetal surface of the amnion, and is frequently present in oligohydramnios....

 is frequently also present (nodules on the fetal surface of the amnion

Amnion

The amnion is a membrane building the amniotic sac that surrounds and protects an embryo. It is developed in reptiles, birds, and mammals, which are hence called “Amniota”; but not in amphibians and fish , which are consequently termed “Anamniota”. The primary role of this is the protection of the...

).

The use of oligohydramnios as a predictor of gestational complications is controversial.

Treatment

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

Amnioinfusion

Amnioinfusion is a method of thinning thick meconium that has passed into the amniotic fluid.It can increase fetal space.It has been used to reduce meconium aspiration syndrome, though evidence of benefit is mixed....

during labor to prevent cord compression.