Amniotic fluid is an essential part of a healthy pregnancy. Too much or too little amniotic fluid may cause complications and will need close monitoring until delivery.

Have you ever heard somebody talk about their “water breaking” before delivery? In this scenario, the “water” doesn’t come out of a bottle. Instead, it’s actually the amniotic fluid, which is fluid that surrounds a baby in the womb.

Read on to learn about amniotic fluid and what conditions could cause complications before delivery.

Amniotic fluid is a clear, yellowish liquid that surrounds a fetus in the amniotic sac. It has antibacterial properties that may ward off infection. The fluid also acts as a source of hydration and nutrients as the fetus grows.

This fluid increases with gestational age up to about 33 weeks, levels off somewhere between 29 and 37 weeks, and may decrease closer to delivery.

In early pregnancy, it consists of salts and substances similar to the mother’s and baby’s blood. Between 22 to 25 weeks, the fluid level changes due to the production of fetal urine. In late pregnancy, the fluid levels are influenced by urine and lung secretions, swallowing, and absorption.

Amniotic fluid cushions the fetus to prevent injury. It also protects the umbilical cord and placenta from compression, ensuring adequate flow of blood, oxygen, and nutrients.

With its antibacterial properties, the amniotic fluid helps shield the fetus from infections and nourishes it by supplying proteins, electrolytes, and vitamins from the mother. The fluid allows the fetus to move around and to practice breathing and swallowing.

These actions are needed for the development of muscles and bones, the lungs, and the digestive system.

Normal levels of amniotic fluid range from 5 centimeters (cm) to 25 cm. Several conditions in pregnancy may impact these levels.

Oligohydramnios

Having low levels of amniotic fluid (less than 5 cm) is referred to as oligohydramnios. Symptoms may include:

Your doctor may diagnose this condition while measuring your belly (it would be small for gestational period) or during a routine ultrasound.

Causes of oligohydramnios include issues with the placenta, maternal conditions (like dehydration or diabetes), pregnancy with multiples, or premature rupture of membranes.

This condition is treated with weekly monitoring of amniotic fluid levels and fetal growth, as well as nonstress tests to catch any potential complications. If your fluid levels remain low, your doctor may recommend delivering early at around 37 weeks of gestation.

Anhydramnios

In some cases, there may be no measurable amniotic fluid surrounding a fetus. This condition is called anhydramnios, and it is a severe form of oligohydramnios.

Anhydramnios is often present from early pregnancy and may result in babies with underdeveloped lungs, significant breathing issues, and skeletal or facial abnormalities.

Many babies affected by anhydramnios are missing both kidneys (bilateral renal agenesis). This condition is also referred to as classic Potter syndrome. There is no treatment for this syndrome. Babies missing both kidneys typically die in utero or shortly after birth.

Polyhydramnios

Too much amniotic fluid (more than 25 cm) is called polyhydramnios.

Symptoms may include trouble breathing, heartburn, and swelling in the legs and feet. You may also have no symptoms, or they may mimic typical pregnancy symptoms.

Your doctor may diagnose this condition while measuring your belly (it would be large for gestational period) or during a routine ultrasound.

Causes of polyhydramnios may include:

It may be treated by monitoring, treating underlying conditions, or having fluid drained with a thin needle. Without treatment, severe cases may lead to premature rupture of membranes, placental abruption, or umbilical cord prolapse.

Leaking amniotic fluid before delivery can be a medical emergency. If you have concerns that your water may have broken, check in with your doctor.

Your doctor can perform pH testing on the fluid to determine what it is and advise on the next steps.

PROM

Premature rupture of membranes (PROM) occurs when the amniotic sac breaks before labor. It can happen at any point during pregnancy but is particularly serious if it happens well before your due date.

This condition is classified as preterm (PPROM before 37 weeks) or term (after 37 weeks) and may increase the risk of infection and other complications.

PROM may happen with no warning or symptoms. It may be caused by things like cervical insufficiency, trauma, infection, and other health conditions.

Treatment depends on the point of pregnancy and involves monitoring, bed rest, and antibiotics. If infection or other complications become a concern, your doctor may induce labor.

The outlook depends on the condition, its severity, and the fetus’s gestation.

Here is an overview of the outlook for the most common conditions that affect amniotic fluid:

Oligohydramnios

In the second trimester, fetuses of pregnant people with oligohydramnios have a low survival rate (10.2%) due to complications like poor lung development.

Babies with oligohydramnios in the third trimester tend to have a better outlook, with a survival rate of 85.3%.

Anhydramnios

Anhydramnios poses significant issues to a fetus if diagnosed before 24 weeks of gestation. The fetus’s lungs and limbs may not develop properly. They may also be at a greater risk of infection, miscarriage, and stillbirth.

Polyhydramnios

Polyhydramnios rarely causes complications unless the condition is severe. In such cases, it may lead to premature birth and low birth weight.

PROM

Around 60% of pregnant people with PROM will go into labor within 24 hours. It increases the risk of neonatal infection by about .5% to 1%.

PPROM is associated with a high risk of:

  • premature birth
  • infections
  • cord problems
  • underdeveloped lungs
  • placental abruption

Keeping up with your regular prenatal appointments is essential for monitoring your amniotic fluid levels as well as your baby’s overall well-being.

If your doctor does identify issues with your fluid levels, they may choose to monitor your pregnancy more closely. Continued monitoring can help your doctor make swift decisions to protect your health and your baby’s health.