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Prenatal genetic and carrier screening

Prenatal screening uses blood tests and ultrasound to estimate the chance of conditions such as Down syndrome; carrier screening checks whether you carry genes for inherited conditions; diagnostic tests (CVS and amniocentesis) take a sample for a definite answer. The decision is how much of this you want to know.

Should we have prenatal genetic and carrier screening?

In short: Parents choose between 5 main approaches: None; Standard screening for common trisomies; Plus expanded carrier panels; Diagnostic testing (CVS, amniocentesis); Maximal information. Evidence: your call. No outcome evidence picks a winner. Preference, culture, money and logistics decide. Best settled: during pregnancy.

Evidence
Your call
Best settled
During pregnancy
Part of
Pregnancy to first birthday

Prenatal genetic and carrier screening: what are the options?

Parents usually land on one of these 5 approaches.

  1. 1. None

    You decline genetic testing during pregnancy.

  2. 2. Standard screening for common trisomies

    You have the routine blood test and ultrasound that estimate the chance of conditions such as Down syndrome.

  3. 3. Plus expanded carrier panels

    You also have blood tests that check whether you each carry genes for a wider range of inherited conditions.

  4. 4. Diagnostic testing (CVS, amniocentesis)

    You have a procedure that takes a small sample from the placenta (CVS) or the fluid around the baby (amniocentesis) to give a definite answer.

  5. 5. Maximal information

    You choose every test on offer, to learn as much as possible before birth.

Prenatal genetic and carrier screening: what does the evidence say?

Your call. No outcome evidence picks a winner. Preference, culture, money and logistics decide.

ACOG: discuss and offer screening and diagnostic testing to every patient regardless of age; every patient may decline

Sources

What else is worth knowing?

Screening tests give a likelihood, not a diagnosis, and a result outside the usual range leads to the offer of a diagnostic test. Diagnostic procedures give a clear answer and carry a small risk of their own. Before choosing, it helps to ask what you would do with each possible result.

Questions to ask each other

  • How much do we each want to know before the birth, and why?
  • What would we do with the results, and would any result change our plans?
  • Would we rather decide together after talking to a genetic counselor?

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First published 2026-10-03. Last updated 2026-10-05. General information, not medical advice.