# Anhydramnios

Anhydramnios is a condition in which there is an abnormally low or complete absence of amniotic fluid surrounding the fetus in the womb. Amniotic fluid is a clear, watery substance that surrounds the fetus. It helps to maintain a constant temperature around the fetus, cushion it from injury, and allows for proper fetal movement and organ development. The cause of anhydramnios is not always clear, but several factors can contribute to its development such as fetal renal abnormalities or placental insufficiency. Untreated anhydramnios can lead to serious complications for the baby, including pulmonary hypoplasia or skeletal deformities.

## Etiology

Although the exact cause of anhydramnios is not always clear, several known factors can contribute to its development. Some of the potential causes include:
* Fetal renal abnormalities: Fetal renal abnormalities can encompass various kidney-related issues, including bilateral renal agenesis, also known as Potter syndrome, which is the most prevalent cause of anhydramnios.
* Placental insufficiency: This is a condition in which the placenta does not function properly, leading to an insufficient supply of oxygen and nutrients to the developing baby, potentially affecting amniotic fluid production.
* Maternal dehydration: Including severe diarrhea, vomiting, or excessive fluid loss can lead to dehydration and decreased amniotic fluid production.
* Fetal growth restriction: Insufficient fetal growth can result in reduced amniotic fluid volume. When the fetus is not growing appropriately, it may have a reduced ability to produce urine, which is a significant contributor to amniotic fluid.
* Maternal dehydration: Arising from conditions such as severe diarrhea, vomiting, or excessive fluid loss that can lead to dehydration and decreased amniotic fluid production.
* Certain medications: Some medications, such as nimesulide and chemotherapeutic agents, have been linked to anhydramnios.

## Diagnosis

Anhydramnios is typically diagnosed through ultrasound examination. During an ultrasound, the amniotic fluid index (AFI) and the single deepest pocket (SDP) will be measured. An AFI of less than 5 cm or an SDP of less than 2 cm indicates oligohydramnios, and an AFI of 0 cm or an absent SDP indicates anhydramnios.

## Prognosis

The prognosis of anhydramnios depends on the underlying cause and the severity of the condition. In general, the prognosis is poor for babies with anhydramnios caused by fetal renal abnormalities, with a high mortality rate. However, the prognosis is better for babies with anhydramnios caused by other factors, such as premature rupture of membranes (PPROM).
Factors that affect the prognosis of anhydramnios include:
* The underlying cause of the anhydramnios: Babies with anhydramnios caused by fetal renal abnormalities have a much poorer prognosis than babies with anhydramnios caused by other factors.
* The severity of the anhydramnios: Babies with severe anhydramnios have a poorer prognosis than babies with mild anhydramnios.
* The gestational age at diagnosis: Babies with anhydramnios diagnosed in the early stages of pregnancy have a poorer prognosis than babies with anhydramnios diagnosed in the later stages of pregnancy.
* The presence of other complications: Babies with anhydramnios who also have other complications, such as fetal growth restriction or skeletal deformities, have a poorer prognosis than babies with anhydramnios who do not have other complications.
With early diagnosis and appropriate treatment, many babies with anhydramnios can be born healthy. However, the prognosis for babies with anhydramnios caused by fetal renal abnormalities remains poor. These babies may require long-term medical care and may have developmental disabilities.

### Symptoms

The symptoms of anhydramnios may not always be apparent, but some potential signs include:
* A decrease in the size of the baby's abdomen
* Decreased fetal movement
* Uterine contractions not associated with pain

### Complications

Untreated anhydramnios can lead to serious complications, including:
* Pulmonary hypoplasia: This is a condition in which the baby's lungs are not fully developed, making it difficult to breathe after birth.
* Skeletal deformities: Anhydramnios can cause the baby's bones to develop abnormally.
* Fetal death: Anhydramnios can increase the risk of stillbirth.

## Treatment

Timely diagnosis and proper intervention for anhydramnios can significantly enhance the outlook for infants affected by this condition. The treatment depends on the underlying cause and may include:
* Amnioinfusion: Injection of amniotic fluid into the womb, can help to improve fetal lung development and reduce the risk of complications
* Fetal monitoring: Close monitoring of the fetus is crucial to assess its well-being and detect any potential complications
* Delivery: The timing of delivery may need to be adjusted depending on the severity of anhydramnios and the health of the fetus