Amniotic Fluid Testing

Amniotic fluid plays a critical role in a healthy pregnancy. This protective liquid surrounds the baby in the womb, cushioning them and supporting the development of vital organs like the lungs and digestive system. Because of its importance, healthcare providers often evaluate the amount and condition of amniotic fluid through specific testing during pregnancy.

What Is Amniotic Fluid Testing?

Amniotic fluid testing is a way to measure the volume and sometimes the quality of the fluid surrounding the baby. These tests help identify if there’s too much fluid (polyhydramnios) or too little (oligohydramnios), both of which can be linked to complications.

There are a few different ways this can be assessed:

1. Ultrasound Evaluation

This is the most common method. During a routine or diagnostic ultrasound, the provider may measure:

• Amniotic Fluid Index (AFI): Measures the depth of fluid in four areas of the uterus. A normal AFI is usually between 5 and 24 cm.

• Single Deepest Pocket (SDP): Measures the deepest visible pocket of fluid. It’s often used in multiple pregnancies.

2. Dye Dilution Test

Rarely used, this involves injecting a dye into the amniotic sac and then withdrawing a sample to measure dilution. It’s typically only done in specific clinical research settings.

3. Amniocentesis

While primarily used for genetic testing or assessing fetal lung maturity, amniocentesis can also evaluate the makeup of the fluid itself, including signs of infection or meconium.

Why Is Amniotic Fluid Testing Important?

Monitoring amniotic fluid can give vital clues about the baby's health. Some reasons your provider might order this test include:

• Measuring fetal growth concerns

• High blood pressure or diabetes during pregnancy

• Premature rupture of membranes

• Decreased fetal movements

• Post-term pregnancy

What If Fluid Levels Are Abnormal?

• Low Fluid (Oligohydramnios): May increase the risk of labor complications, fetal growth issues, or cord compression. Treatment may include increased monitoring, hydration, or early delivery depending on severity.

• High Fluid (Polyhydramnios): Can be linked to gestational diabetes, twin pregnancies, or fetal anomalies. Management depends on the underlying cause.