Can the scan be wrong?

Yes, and in both directions. It flags feet that turn out normal, and it misses feet that turn out real. Neither is a failure. It is what happens when you judge stiffness from a picture.

Written by Heath, who has lived it: casts from birth, a fusion at sixteen, the US Army, and distance running.

Where are you

Four situations, and they need genuinely different things from you. Pick yours.

Choose the situation you are actually in.

The scan said clubfoot

This is the most common starting point, and the honest framing is that you have a strong indication and not a diagnosis. A meaningful proportion of flagged feet are entirely normal at birth. Usually because they were positional, or because the viewing angle was poor.

That is not false comfort. It is the reason your team said “suspected”, not “confirmed”, and the reason nobody can tell you severity or cast numbers yet.

DoArrange the orthopedic referral now. Canceling is easy; catching up is not.

Do notResearch treatment in depth yet. You may be preparing for something that is not there.

AskWas the view good? Are both feet involved? Is anything else being checked?

ExpectA follow-up scan, and a definitive answer only after birth.

They said they were not sure

Genuinely the hardest position, because there is nothing to plan around. Uncertainty usually comes from a poor view. The baby lying awkwardly, a foot pressed against the wall of the uterus, or a late scan where space has run out.

The useful thing to know is that uncertainty is not a middle severity. It says nothing about the foot; it says something about the picture.

DoAsk whether another scan is planned, and at what gestation.

Do notRead a hedge as a soft yes. It is not evidence either way.

AskWhat specifically was unclear: the angle, the view, or the finding itself?

ExpectTo still be uncertain until the birth. That is normal and not neglect.

The finding changed between scans

Common, and it goes both ways. A foot flagged at twenty weeks can look normal at twenty-eight, and occasionally the reverse. Neither means a clubfoot (talipes equinovarus, CTEV) corrected or developed. It means one of the two views was better.

Weight the earlier scan more heavily if the later one was after about thirty-two weeks. Late scans have less room and poorer angles, so a reassuring late scan is weaker evidence than it feels.

DoAsk which scan the team considers more reliable, and why.

Do notAssume improvement means resolution. See can it correct itself.

AskWas the second view actually clearer, or just different?

ExpectThe examination after birth to settle it regardless.

No warning, and now they have it

This happens, and it is not evidence anyone was careless. Feet get missed when they are tucked against the uterine wall, when the baby will not move, or when a scan was late. Some babies with clubfoot have unremarkable scans the whole way through.

The shock is real and worth naming. You had no preparation time and everyone else seems to know what happens next. But nothing has been lost. Treatment starts in the first weeks either way, and a prenatal diagnosis buys planning, not outcome.

DoGet the referral moving. That is the only time-sensitive thing.

Do notSpend energy on why it was missed. It changes nothing clinically.

AskHow soon can casting start, and who is the Ponseti provider?

ExpectTo feel behind for two weeks. You are not. See what clubfoot is.

Why it goes wrong in both directions

	What happened	Usual reason
Flagged, but fine	Scan suspected clubfoot; feet normal at birth	A positional foot, or an awkward viewing angle
Missed entirely	Scans clear; clubfoot found after birth	Foot tucked away, baby not moving, or a late scan
Wrong count	One foot flagged; both affected, or the reverse	One foot viewable, the other not

All three trace to the same limitation. Ultrasound sees shape. Clubfoot is defined by stiffness. A scan is reading the one clue available to it, and a positional foot and a clubfoot can produce an identical picture.

The numbers

How often the scan is wrong, and how often it is incomplete

In a cohort of 423 pregnancies where the scan showed clubfoot and nothing else, 10 percent of babies did not have clubfoot after birth. A different kind of surprise was more common than people expect: in 12 percent, something else was found after birth, and it was classed as major in 9 percent.10

A smaller series of 66 followed pregnancies put the false-positive rate at 13.6 percent.11 So the scan is usually right about the foot, and a finding of isolated clubfoot is a starting point rather than a guarantee.

The system is set to over-flag deliberately

Being told your baby may have clubfoot when they do not is distressing, and it is also the system working correctly. Missing a clubfoot costs weeks of the window where newborn tissue responds best. Flagging a normal foot costs an appointment and some worry. Screening is tuned accordingly, and it is the right way round.

Scan accuracy

How can I tell if my baby has clubfoot on an ultrasound?

You cannot, and neither can a still image on a screen. What the sonographer is looking for is the foot and the lower leg appearing in the same plane, which is what happens when the foot is turned in rather than pointing away. That view is also produced by a foot being held awkwardly and by the angle the scan was taken at, which is the reason a prenatal finding is an indication to look again rather than a diagnosis. The diagnosis is made by hand, after birth, on flexibility.

Should I ask for a second scan?

A follow-up is usually offered anyway. It is reasonable to ask how confident the view was and whether another look is planned, particularly if the finding came from a late scan where conditions are poorer.

Did the sonographer make a mistake?

Usually not. Flagging a foot that turns out normal is the system behaving correctly. It is set to catch things and not to be certain, because the cost of a missed clubfoot is higher than the cost of a check.

Would a 3D scan be clearer?

It can give a clearer picture of shape, which some parents find helpful. It cannot assess stiffness, so it does not resolve the actual question any more definitively than a standard scan.

Can clubfoot be misdiagnosed on ultrasound?

Yes, in both directions. A scan can flag a foot that is entirely normal at birth, and it can miss a foot that turns out to be clubfoot. Neither is unusual, because a scan sees shape and the diagnosis depends on stiffness.

How often is a prenatal clubfoot finding wrong?

It varies by center and scan. In a Dutch cohort of 423 babies thought to have isolated clubfoot, 10 percent turned out not to have clubfoot after birth, and a smaller series found 13.6 percent. That is why every finding is described as suspected.

What is a false positive on a clubfoot scan?

A scan suggesting clubfoot when the baby is born with normal feet. The usual explanations are a positional foot held bent by crowding, or an awkward viewing angle that made a normal foot look turned.

Can a scan miss clubfoot completely?

Yes. A foot tucked against the uterine wall, positioned awkwardly, or scanned late when space is tight can be hard to view. Some babies with clubfoot have entirely unremarkable scans throughout pregnancy.

Does a false positive mean the sonographer made a mistake?

Usually not. Flagging a foot that turns out normal is the system behaving correctly. It is set to catch things, not to be certain, because the cost of a missed clubfoot is higher than the cost of a check.

What should I do while waiting to find out?

Arrange the orthopedic referral anyway. If the feet are fine you cancel an appointment. If they are not, you have saved the first weeks, which are the most valuable ones in treatment.

Can a 3D scan give a clearer answer?

It can give a clearer picture of shape, which some parents find helpful. It cannot assess stiffness, so it does not resolve the actual question any more definitively than a standard scan does.

Sources

Where this comes from

1 Fetal Anomalies Consult Series #2: ExtremitiesSociety for Maternal-Fetal Medicine 2 Ruzzini L, et al. Prenatal diagnosis of clubfoot: where are we now? Systematic review and meta-analysisDiagnostics, 2021 3 Adhiyaman A, et al. Prenatal counseling for congenital clubfootJournal of the Pediatric Orthopaedic Society of North America, 2024 4 Fantasia I, et al. Prenatal diagnosis of isolated clubfoot: diagnostic accuracy and long-term postnatal outcomesEuropean Journal of Obstetrics, Gynecology and Reproductive Biology, 2021 5 Abdallah W, Nassar M. Outcome of prenatal diagnosis of clubfoot: a single institution experienceFuture Science OA, 2022 6 Sahin R, et al. Prenatal diagnosis and postnatal follow-ups of 38 clubfoot cases in a tertiary reference centerRevista da Associação Médica Brasileira, 2024 7 Kim YM, et al. Improving prenatal diagnosis precision for congenital clubfoot by using three-dimensional ultrasonographyDiagnostics, 2024 8 Lauson S, et al. Outcome of prenatally diagnosed isolated clubfootUltrasound in Obstetrics and Gynecology, 2010 9 Mammen L, Benson CB. Outcome of fetuses with clubfeet diagnosed by prenatal sonographyJournal of Ultrasound in Medicine, 2004 10 Can Prenatal Ultrasound and Genetic Testing Reliably Exclude Non-Isolated Clubfoot?de Vries et al. Prenat Diagn, 2026. PMID 41402700 11 Fetal congenital talipes equinovarus: genomic abnormalities and obstetric follow-up resultsCai et al. J Matern Fetal Neonatal Med, 2024. PMID 38151241

Whichever way it goes

What they saw →The finding itself, week by week. Positional or not →The five checks that settle it after birth. Find a provider →Worth doing now, either way. Found on the 20-week scan →What a prenatal diagnosis does and does not tell you. The whole timeline →Birth to adulthood, and where each stage sits.