Patau Syndrome Screening: Complete Guide
Patau syndrome (trisomy 13) is one of the three chromosomal conditions routinely screened for in UK antenatal care, alongside Down's syndrome and Edwards' syndrome. It's a rare and serious condition, and being offered screening for it can feel daunting — this guide explains what the screening actually involves and what a result might mean.
What Patau syndrome is
Patau syndrome happens when a baby has an extra copy of chromosome 13 in their cells, rather than the usual two copies. This extra genetic material disrupts normal development, typically causing significant physical differences and severe developmental issues that affect multiple body systems. It's one of the rarer trisomies screened for antenatally, and sadly, most babies with Patau syndrome do not survive pregnancy or the first weeks of life, though a small number of children live longer with complex, ongoing care needs.
How screening for it works
Patau syndrome screening isn't a standalone test — it's built into the same screening pathways used for Down's and Edwards' syndromes:
- The combined test, offered between roughly 11 and 14 weeks, combines a blood test with the nuchal translucency measurement taken during your dating scan to estimate a chance figure for all three conditions.
- If you book later in pregnancy, the quadruple test (a blood test alone, without the scan measurement) is offered instead, generally between 14 and 20 weeks.
- Non-invasive prenatal testing (NIPT) can be used as a more accurate second step if your first-line result comes back higher chance, or it may be accessed privately.
- All of these are screening tests that estimate a probability — none of them diagnose Patau syndrome outright.
What happens after a higher-chance result
If your screening result shows a higher chance of Patau syndrome, your midwife or obstetric team will talk you through what that means for your specific result and offer you an appointment with a specialist, often alongside a fetal medicine team. You'll usually be offered a diagnostic test — either CVS or amniocentesis — which samples cells directly to confirm or rule out the diagnosis. Nobody is obliged to have diagnostic testing, and your team should support whatever decision feels right for you, including choosing not to test further.
Frequently Asked Questions
How common is Patau syndrome?
Patau syndrome is very rare, affecting a small number of pregnancies. It's one of the less common conditions screened for as part of combined, quadruple, or NIPT testing during pregnancy. Because it's so rare, most women who are screened will never receive a higher-chance result for this specific condition.
What happens if my baby is diagnosed with Patau syndrome?
If a diagnostic test confirms Patau syndrome, your care team will explain what this means for your individual pregnancy and talk through your options and choices in detail, without pressure either way. Many hospitals can connect you with a specialist midwife, genetic counsellor, or fetal medicine team who focus specifically on supporting families through this diagnosis. Whatever you decide, ongoing emotional support and follow-up care should be offered throughout.
Is there support available for families affected by Patau syndrome?
Yes — UK charities that specialise in supporting families affected by rare chromosomal conditions can offer information, peer support, and guidance alongside your NHS care team. Your midwife, obstetrician, or a hospital bereavement or specialist support service can point you towards relevant local and national resources. You don't have to navigate a diagnosis like this without support, and asking your team for a referral is a reasonable and common request.
This article is for informational purposes only and does not constitute medical advice.
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