What does the quad screen in pregnancy check?

What does the evidence say about quad screen in pregnancy?

1. The four measured substances are AFP, hCG, unconjugated estriol, and inhibin A. The laboratory combines them with details such as gestational age. An incorrect pregnancy date can affect the estimate, so the care team may check dating before interpreting an unexpected result. 1
2. ACOG describes the quad screen as an option between 15 and 22 weeks. The laboratory accepting your sample may use a narrower window. Confirm the booking deadline with the ordering practice rather than waiting until the last day of a general online range. 2
3. Screening sorts pregnancies into higher- and lower-chance groups; false alarms and missed findings can occur. A positive screen is a reason for an explanation of the next choices, not a conclusion about the baby or a substitute for individualized counseling. 3
4. Cell-free DNA screening examines a different signal and has different limits. It does not check for open neural tube defects. If you already had NIPT, ask whether the proposed blood draw is AFP alone or another chromosome screen, and why it is being ordered. 4
5. Amniocentesis can provide fetal cells and amniotic fluid for selected follow-up tests. It has benefits and procedural risks that deserve a separate discussion. A high-chance quad result does not make that procedure mandatory; clarify what the offered test would and would not answer. 5

When should you plan the quad screen and follow-up?

• First trimester. Discuss available screening approaches before committing to a testing sequence.
• Second trimester. Confirm the laboratory window and arrange a conversation about the result.
• Third trimester. If a concern remains unresolved, ask which testing or newborn-care arrangements are still useful.

Questions to bring to your prenatal team