The Fetal Amniotic Fluid Maximum Pocket Diameter test is a safe, painless prenatal ultrasound that measures the deepest vertical pocket of fluid surrounding your baby, helping your healthcare provider evaluate whether your amniotic fluid level is normal, low, or high and guide any additional monitoring or care needed during pregnancy.
An ultrasound test that identifies and measures the deepest vertical pocket of amniotic fluid surrounding your baby, helping assess fetal well-being and detect whether fluid levels are too low or too high during pregnancy.
{"Measures the deepest single vertical pocket of amniotic fluid","Helps evaluate fetal kidney function and fluid balance","Used to diagnose and monitor oligohydramnios (low fluid) or polyhydramnios (excess fluid)","Part of routine prenatal ultrasound assessments","Non-invasive and safe for both mother and baby"}
Key facts at a glance
- LOINC
- 11832-3
- Short code
- Fet AF space Diam.lgst pct max US.meas
- Synonyms
- Fet AF space Diam.lgst pct max US.meas
- Category
- cardiac
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-measured
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What is this test?
The Fetal Amniotic Fluid Maximum Pocket Diameter test is an ultrasound measurement that identifies and measures the deepest vertical pocket of amniotic fluid surrounding your baby. This single measurement helps healthcare providers assess the total amount of amniotic fluid, which is crucial for fetal development and health.
How is the test performed?
During a standard ultrasound exam, the sonographer will scan your uterus to find the deepest pocket of amniotic fluid. They will measure this pocket vertically (perpendicular to the floor) in centimeters. This is called the Maximum Vertical Pocket (MVP) or Single Deepest Pocket (SDP) measurement. The procedure is painless and similar to other prenatal ultrasounds.
What do the results mean?
The measurement helps categorize your amniotic fluid level: Normal amniotic fluid is generally considered to be 2-8 cm for the deepest pocket. Oligohydramnios (low fluid) is when the measurement is less than 2 cm, which may indicate kidney problems, membrane rupture, or placental issues. Polyhydramnios (excess fluid) is when the measurement is more than 8 cm, which may be associated with gestational diabetes, fetal abnormalities, or other conditions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This measurement is a key indicator of fetal well-being. Amniotic fluid is produced by the fetus's kidneys (from fetal urine), so the amount reflects fetal kidney function and urinary output. Abnormal levels may indicate underlying fetal, placental, or maternal conditions that require further investigation or intervention. This test is particularly important in high-risk pregnancies and for monitoring fetal growth restriction.
Frequently asked questions
Is this test safe?
Do I need to prepare for this test?
How often is this measurement taken?
What happens if my fluid levels are abnormal?
Sources
- 1
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Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy