Inhibin A, Serum

Inhibin A, Serum

What it is

The Inhibin A, Serum test measures the level of inhibin A, a hormone produced mainly by the ovaries in women and the testes in men. Inhibin A plays a role in regulating follicle-stimulating hormone (FSH) and is important in reproductive physiology. In clinical practice, serum inhibin A is primarily used in pregnancy screening and in evaluating certain ovarian conditions.

Uses

This test is used to:

• Assess maternal risk for chromosomal abnormalities (such as Down syndrome and Trisomy 18) as part of the second-trimester “quadruple screen.”
• Monitor ovarian function and evaluate some cases of infertility.
• Assist in diagnosis and monitoring of ovarian granulosa cell tumors.
• Support research or specialized endocrine evaluations involving reproductive hormones.

Symptoms / Conditions That May Lead to the Test

Doctors may recommend this test if you have:

• Pregnancy, as part of routine prenatal screening for fetal chromosomal disorders.
• Unexplained infertility or irregular menstrual cycles.
• Suspicion of an ovarian tumor, especially granulosa cell type.
• Participation in an advanced reproductive health evaluation.

Abnormal Results

• Elevated Inhibin A in Pregnancy: May be associated with increased risk of chromosomal abnormalities such as Down syndrome, but must be interpreted along with other markers (AFP, hCG, estriol) in the quad screen.
• Low Inhibin A in Pregnancy: May suggest risk of Trisomy 18 or other chromosomal disorders.
• Elevated Inhibin A (non-pregnant): May indicate ovarian granulosa cell tumor or abnormal ovarian function.
• Low Levels (non-pregnant): May reflect impaired ovarian reserve or reduced reproductive function.

Results are interpreted in combination with other hormone tests, imaging, and clinical findings.

Risks

The test requires a blood sample and carries minimal risks, including:

• Mild pain, bruising, or discomfort at the puncture site.
• Rare chance of infection or dizziness after blood draw.