What this test measures
PAPP-A (Pregnancy-Associated Plasma Protein A) is a metalloproteinase produced in large amounts by the syncytiotrophoblast of the developing placenta. Its main function is to cleave IGF-binding proteins, releasing free IGF-1 and IGF-2 — both critical for early placental development and foetal growth.
In maternal serum, PAPP-A rises steeply through the first trimester, peaking around 12–13 weeks. Values are expressed as Multiples of the Median (MoM). Reduced PAPP-A (<0.4 MoM) is associated with chromosomal abnormalities (trisomy 21, 18, 13) and — independently — with adverse pregnancy outcomes (pre-eclampsia, foetal growth restriction, preterm birth, stillbirth) due to underlying placental dysfunction.
Why it matters
PAPP-A is one of the two biochemical markers (with free β-hCG) used in the first-trimester Dual / Double Marker screen — together with NT ultrasound, this combination detects ~85–90% of Down syndrome cases at a 5% false positive rate. Low PAPP-A by itself is also clinically meaningful: it identifies women at higher risk of pre-eclampsia and IUGR, and the FMF / RCOG / FOGSI all recommend considering low-dose aspirin from 12 weeks in women with low PAPP-A plus other risk factors.
In Indian practice, PAPP-A is almost always reported as part of the Dual Marker rather than as a standalone test. A standalone PAPP-A request usually comes when only a partial result is available or for repeat sampling in unusual clinical scenarios.
How to prepare
No fasting required. Schedule the blood draw between 11+0 and 13+6 weeks gestation, ideally close to the NT ultrasound. Disclose IVF/IUI conception, twins, smoking status, ethnicity, weight, and any prior pregnancy losses on the request form — all influence MoM calculation.
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| PAPP-A (mIU/L (or MoM))[1][2] | Median MoM = 1.0 (range 0.5–2.0 typical) | Low PAPP-A MoM (<0.4) is associated with trisomy 21, 18, and 13 — and, independently, with placental dysfunction: pre-eclampsia, foetal growth restriction (IUGR), preterm birth, and stillbirth. Many obstetricians use a low PAPP-A as a trigger to start low-dose aspirin (75–150 mg) from 12 weeks and to schedule extra growth scans. | High PAPP-A MoM is generally not associated with chromosomal abnormality or adverse outcome. |
PAPP-A interpretation in the first trimester
| PAPP-A MoM | Likely meaning | Action |
|---|---|---|
| 0.5 – 2.0 | Normal | Routine antenatal care |
| 0.4 – 0.5 | Borderline low | Repeat risk discussion; monitor growth |
| < 0.4 | Low — placental dysfunction risk | Low-dose aspirin from 12 weeks; serial growth scans |
| < 0.4 + abnormal NT or β-hCG | Chromosomal risk | Genetic counselling + NIPT / CVS |
Frequently asked questions
What is PAPP-A?
PAPP-A (Pregnancy-Associated Plasma Protein A) is a protein made by the placenta. It is measured in the first-trimester Dual Marker screen alongside free β-hCG.
When is PAPP-A tested?
Between 11+0 and 13+6 weeks of gestation, typically alongside the NT ultrasound.
What does a low PAPP-A mean?
Low PAPP-A (<0.4 MoM) is associated with chromosomal abnormalities and with placental dysfunction (pre-eclampsia, growth restriction, preterm birth). Even if your chromosomal risk score is reassuring, a low PAPP-A may prompt your obstetrician to start low-dose aspirin and arrange extra growth scans.
Do I need to fast?
No fasting is required.
My PAPP-A is 0.3 MoM — am I going to have problems?
Not necessarily. Most women with low PAPP-A still have healthy pregnancies. The low value is a flag for closer monitoring, not a diagnosis. Discuss with your obstetrician.
Will aspirin help?
Low-dose aspirin (75–150 mg daily from 12 weeks) reduces pre-eclampsia risk by ~60% in women identified as high risk via PAPP-A and other markers. The decision is made by your obstetrician based on overall risk.
Is PAPP-A useful outside the first trimester?
Not as a screen — PAPP-A levels in maternal serum decline rapidly after delivery and the assay is calibrated for the 11–13 week window. It has been used in research as a cardiac risk marker outside pregnancy but not in routine clinical practice.
Can my PAPP-A be repeated?
It is rarely repeated because the result is gestational-age-specific. If the first sample was taken outside the 11–13 week window, a repeat within the correct window can be useful.
Related Pregnancy / Prenatal tests
Tests commonly ordered alongside PREGNANCY ASSOCIATED PLASMA PROTEIN A, or that help interpret an unexpected result.
Sources & references
- NCBI StatPearls — Pregnancy-Associated Plasma Protein A · accessed 2026-05-30T00:00:00.000Z
- ACOG — Screening for Fetal Chromosomal Abnormalities · accessed 2026-05-30T00:00:00.000Z
- Fetal Medicine Foundation — 11–13 Weeks Scan · accessed 2026-05-30T00:00:00.000Z
Book with Zelnoo
Get your PREGNANCY ASSOCIATED PLASMA PROTEIN A test done at home — transparent prices, NABL-accredited labs.
Zelnoo lets you compare diagnostic test prices across NABL-accredited labs in Mumbai & Thane, book a free home phlebotomist visit, and receive digital reports in 24–48 hours into a consent-first report vault. No subscriptions, no membership fees — pay only for the test you book.
Book PREGNANCY ASSOCIATED PLASMA PROTEIN A now