Diagnostic accuracy of isolated clubfoot in twin compared to singleton gestations

Background Our objective was to determine the predictive value of the prenatal diagnosis of isolated clubfoot in twin gestations compared to singleton gestations. Methods A prospectively entered ultrasound database was reviewed for all pregnancies scanned at our institution from 2002 to 2014. Cases of suspected clubfoot were identified. Neonates with associated anomalies or aneuploidy, and patients who delivered at other institutions were excluded. Neonatal charts were reviewed for the confirmation of clubfoot. The chi-squared (χ2) test, Fisher's exact test and the Mann-Whitney U test were used in the analysis, with p < 0.05 considered significant. Results Of those women who had prenatal ultrasound and subsequently delivered at our hospital, 84 pregnancies had isolated clubfoot suspected in the antenatal period. Of these pregnancies, 20 were twin gestations and 64 were singleton gestations. Overall, 51/84 (60.7%) pregnancies had clubfoot confirmed during the neonatal period. Of the twin pregnancies, only 35% (7/20) had a confirmed diagnosis of clubfoot at birth compared to 68.8% (44/64) of the singleton pregnancies (P = 0.008). Gestational age at diagnosis, breech presentation, neonatal gender, unilateral vs. bilateral clubfoot and suspicion of clubfoot in the presenting twin (Twin A) vs. the non-presenting twin (Twin B) did not correlate with an accurate diagnosis of clubfoot in twins. Conclusion False-positive prenatal diagnosis of isolated clubfoot is more common in twin gestations compared to singletons. This may be due to transient malpositioning or a result of diminished space. Obstetric providers should consider the possibility of a false-positive diagnosis and use caution when counseling patients about a prenatal suspicion for clubfoot, especially in twin gestations.