BACKGROUND AND PURPOSE:

• Common prenatal ultrasound finding with varying severity and may be isolated or complex (presence of additional anatomical findings)
• There is controversy as to whether isolated clubfoot requires additional invasive testing to determine karyotype
• Weiner et al. (Prenatal Diagnosis, 2017) examined the diagnostic accuracy, related findings, and outcomes of pregnancies with prenatal detection of clubfoot

METHODS:

• Retrospective study of 40,320 routine prenatal anatomy scans
• Clubfoot detected during routine scan at 14-16 weeks or 21-24 weeks gestation
• Sonographic characteristics, pregnancy work-up, and postnatal outcomes were evaluated

RESULTS:

• Clubfoot was diagnosed in 0.37% (150) prenatal ultrasound anomaly scans
• Following exclusion for missing information, 109 fetuses remained for analysis
• Bilateral and unilateral clubfoot were diagnosed in 46.7% and 53.2%, respectively
• Isolated presentation in 69.7% and complex in 30.2%
• 44% of fetuses underwent invasive diagnostic testing
  • 12.5% of fetuses sampled had abnormal karyotype (5.5% of overall cohort)
  • 2 cases of trisomy 18, 1 Down syndrome, 1 unbalanced translocation and 2 lost to follow up
  • Findings were all complex cases
  • Microarrays were used in some of the studies for chromosomal analysis
• Diagnosis was confirmed in 71.4% cases of liveborn infants
• Sonographic diagnoses was verified postpartum more often in singletons than twins (p=0.05)
• In singletons, 11.1% of cases were misdiagnosed as isolated, and later found to be accompanied by additional abnormalities postpartum
• 57.1% of complex cases were verified postpartum
• Bilateral clubfoot was verified postpartum more often than unilateral (87.9% vs. 65.9%; p=0.03)
• Bilateral clubfoot resulted in more surgical interventions postnatally
• Approximately 58% of cases overall required surgical treatment

CONCLUSION:

• Overall high false positive rate, which is higher in twins likely due to a positional effect
• Additional anomalies lower than typically reported, at only 30.2%
  • May reflect low risk population
• Prenatal ultrasound diagnosis of clubfoot is more accurate in singletons with bilateral clubfoot
• Bilateral findings did not increase risk for additional anomalies
• This study suggests karyotyping should be considered even with isolated clubfoot because 11.1% of isolated cases ended up being complex at birth

Learn More – Primary Sources:

Diagnostic accuracy, work-up, and outcomes of pregnancies with clubfoot detected by prenatal sonography

Related ObG Topics:

Prenatal Detection of Clubfoot – Key Points

Trisomy 18 – Key Findings, Prenatal Screening and Prognosis

CDC Guidance on Zika and Pregnancy