Leaking Amniotic Fluid: What It Looks Like & What to Do

Leaking amniotic fluid can lead to complications for the baby, including changes in development, fetal growth restriction, trauma, and umbilical cord compression. Because amniotic fluid supports the baby throughout pregnancy, a drop in fluid can increase risk.

Amniotic fluid helps regulate temperature, allows the baby to move and develop, and protects against infection and injury. When the amount of fluid decreases, the baby may be more vulnerable to several problems.

A reduced amount of amniotic fluid is called oligohydramnios, and it can happen at any point in pregnancy. It should be evaluated by an obstetrician to help identify the cause and guide the safest treatment.

What does leaking amniotic fluid look like?

Leaking amniotic fluid is often noticed by how it looks and feels: it tends to be clear, watery, and odorless, or it may have a slightly sweet smell.

Amniotic fluid can leak in small amounts (like a slow, steady trickle) or come out in larger amounts and continue leaking.

According to the American College of Obstetricians and Gynecologists (ACOG), standard diagnosis commonly includes a speculum exam to check for fluid pooling with bedside testing (such as nitrazine/ferning or biochemical tests), with ultrasound used as needed to assess amniotic fluid.

Possible causes

The main causes of leaking fluid during pregnancy are:

1. Premature rupture of membranes

Premature rupture of membranes (PROM) occurs when the amniotic sac breaks before 37 weeks of pregnancy, causing the amniotic fluid to leak either slowly as a trickle or more suddenly as a gush.

It may be associated with a prior history of premature rupture of membranes, a short cervical length, deficiencies in copper or vitamin C, or cigarette and drug use during pregnancy.

Other possible causes include having a low body mass index (BMI) or vaginal bleeding during pregnancy in the second or third trimester.

2. Congenital abnormalities in the fetus

Certain fetal congenital abnormalities, particularly those involving the kidneys or urinary tract, can cause amniotic fluid leakage after about 16 to 20 weeks of pregnancy.

These conditions may impair fetal urine production or outflow, resulting in decreased amniotic fluid volume.

3. Placental problems

Some placental problems, such as placental abruption or twin-to-twin transfusion syndrome, can cause leaking amniotic fluid.

Placental abruption happens when the placenta separates from the uterus before labor, which can cause heavy vaginal bleeding or severe, constant abdominal pain.

Twin-to-twin transfusion syndrome is caused by an imbalance in placental blood flow in identical twin pregnancies.

As a result, one fetus receives more blood than the other, and the fetus who receives less blood produces less urine, which lowers the amount of amniotic fluid.

4. Maternal complications

Some maternal complications, such as high blood pressure during pregnancy, preeclampsia, dehydration, or gestational diabetes, can contribute to leaking amniotic fluid and lower overall fluid levels.

5. Post-term pregnancy

Late-term pregnancy (41 weeks 0 days to 41 weeks 6 days) and postterm pregnancy (≥42 weeks 0 days) are associated with decreased amniotic fluid volume.

These conditions may also compromise fetal oxygenation and nutrient supply if placental function declines.

Possible complications

Leaking fluid during pregnancy can lead to complications for the fetus, such as:

• Fetus smaller than expected for gestational age;

• Delayed growth or delayed lung and kidney development;

• Decreased fetal movement, which may cause muscle atrophy;

• Higher risk of umbilical cord compression;

• Higher risk of serious infections or trauma;

• Breathing difficulties.

In addition, leaking amniotic fluid may result in stillbirth or miscarriage, especially when the fluid loss is heavier and happens in the first half of pregnancy, up to week 24.

Lower amounts of amniotic fluid can also make it harder to see the fetus clearly on ultrasound, which can make fetal abnormalities more difficult to identify.

What to do

If leaking amniotic fluid is suspected, an obstetrician should evaluate it as soon as possible to confirm whether membranes have ruptured and whether amniotic fluid levels are low.

Regular prenatal visits are also important so an obstetrician can monitor amniotic fluid and overall fetal well-being throughout pregnancy.

If fluid loss is heavy and accompanied by symptoms such as vaginal bleeding, contractions, dizziness, swelling, or rapid weight gain, emergency care is needed right away.

Treatment options

Treatment for leaking amniotic fluid during pregnancy should be guided by an obstetrician and depends on gestational age, signs of infection, fetal status, and whether labor has started.

Evaluation often includes confirming membrane rupture and assessing amniotic fluid by ultrasound, commonly using objective measurements such as amniotic fluid index (AFI) or the single deepest pocket.

The following may be recommended:

• Maternal hydration, where the mother receives fluids (often by IV) when clinically appropriate;

• Amnioinfusion, where sterile saline is placed into the amniotic cavity in specific clinical situations to help restore fluid temporarily.

Delivery is usually recommended at 37 weeks or later (often by induction if labor doesn’t start), often recommended or considered at 34–36 weeks, and expectant management with close monitoring is commonly used before 34 weeks when appropriate.

Doctors may use medications in certain situations, such as antibiotics to reduce infection risk and prolong pregnancy and corticosteroids to support fetal lung development. According to the CDC, intrapartum antibiotics are also used for prevention of group B strep disease in newborns when clinically indicated.

Leaking fluid during labor

If someone goes into labor with low amniotic fluid, the OB/GYN or midwife may place a small tube into the uterus and infuse sterile fluid during a vaginal delivery.

This can help prevent problems like reduced oxygen to the fetus, which can happen if the umbilical cord becomes compressed between the mother and baby.

However, this approach does not treat low amniotic fluid during pregnancy, because it only works while the fluid is being infused during labor.

Low amniotic fluid

Amniotic fluid is typically checked on ultrasound using either the amniotic fluid index (AFI) or the single deepest vertical pocket (SDP).

Typical ultrasound ranges used in routine care (most often in the 2nd and 3rd trimesters) include:

• AFI: about 5 to 24 cm is generally considered within the expected range. 5 cm or less is commonly used to define oligohydramnios (low amniotic fluid);

• SDP: about 2 to 8 cm is generally considered within the expected range. Less than 2 cm is commonly used to define oligohydramnios.

Overall, amniotic fluid tends to increase through mid-pregnancy, reach its highest levels in the early third trimester, and then slowly decrease as delivery gets closer.