Nitric Oxide in Amniotic Fluid (via Mass Concentration)

Why This Test Is Done

Your healthcare provider may recommend this test if you’re at risk for preterm labor or if you’re nearing your due date. It’s often performed during a procedure called an amniocentesis, where a small amount of amniotic fluid is collected from your uterus for analysis. This test is typically done to check if your baby’s lungs are mature enough to function outside the womb.

What to Expect Before the Test

You’ll likely be monitored closely during the procedure, which may include a brief stay in the hospital. You may feel mild cramping or pressure, but it’s usually not painful. Your provider will explain how to prepare, including any restrictions on food, fluids, or medications before the test.

What the Results Mean

The test measures nitric oxide levels, which are linked to the production of surfactant—a substance that helps keep your baby’s lungs inflatable. Higher levels of nitric oxide often indicate healthy lung development. Results are usually reported as a ratio or qualitative assessment rather than a single numeric value.

Possible Outcomes and Next Steps

If the test shows low nitric oxide levels, your provider may recommend additional tests or interventions to support fetal lung development, such as corticosteroids to help mature the lungs further. If levels are high, it may suggest less concern for respiratory issues, but further evaluation may still be needed.