NT Scan Bloodwork (PAPP-A, free beta-hCG) in Pregnancy — What It Means

When is it done?

Blood is taken between 10 and 13+6 weeks. It is paired with the nuchal translucency ultrasound. That scan is done at 11 to 13+6 weeks.

Why is it done in pregnancy?

The first-trimester combined test pairs the blood markers with the NT scan. It is one of the most accurate risk checks available in early pregnancy that does not need a needle into the womb. It gives early information and, if needed, early options for further checks.

About the reference range

PAPP-A and free beta-hCG are not read against fixed numeric ranges. They are given as multiples of the median (MoM) for your exact pregnancy stage. They are used within validated risk software, with the NT measurement and your details. Raw values without this software and context are not meaningful on their own.

What to discuss with your obstetrician

Ask your obstetrician for the combined risk figure, not just the raw blood values. Also ask what it means for your pregnancy. And ask if further checks, such as cell-free DNA testing, are advised and what the next steps are.

Frequently asked questions

What does a low PAPP-A level mean?

A low PAPP-A, usually below 0.4 MoM, can raise the risk estimate for certain chromosomal conditions. It is also linked with some placental problems later in pregnancy. Your obstetrician will read this within the full combined risk. They may advise more monitoring.

What does a high free beta-hCG level mean?

A high free beta-hCG, usually above 2.0 to 2.5 MoM, shifts the combined risk estimate upward. This is for certain chromosomal conditions. On its own it is not a finding. It is one input into the overall risk that your obstetrician reviews.

Can I have the NT scan without the blood test?

The NT scan alone gives some information. But the combined test, using blood markers, the NT measurement, and your age, performs much better than NT alone. Your obstetrician or sonologist can advise on what your facility offers.

What is the difference between this combined test and cell-free DNA (NIPT) testing?

The combined test is a risk estimate using indirect markers. Cell-free DNA (NIPT) looks at placental DNA in your blood and has higher accuracy for common chromosomal conditions. But it costs more and is still a risk check, not a firm answer. Your obstetrician can help you choose.

If the combined risk is high, does that mean something is definitely wrong?

No. A high-risk result means the estimate is above a threshold and needs more discussion. Most pregnancies with a high-risk result are unaffected. Further checks, such as NIPT or a needle test, can give more information.

Sources

• Fetal Medicine Foundation (FMF) (2022) — FMF Guidelines: First Trimester Combined Screening for Chromosomal Abnormalities
• ACOG (2020) — ACOG Practice Bulletin No. 226: Screening for Fetal Chromosomal Abnormalities
• FOGSI (2021) — FOGSI Good Clinical Practice Recommendations: First Trimester Screening