Isolated polydactyly: prenatal diagnosis and perinatal outcome.

Our objective was to determine the clinical significance of isolated polydactyly identified on prenatal sonogram. All patients with sonographically detected isolated polydactyly scanned over an 11-year period were identified from our database. All patients underwent detailed surveys, and follow-up was obtained by review of the medical records and telephone conversations with parents and referring physicians. Thirteen patients with isolated polydactyly were identified. Follow-up was available in 12 patients. Indications for referral included advanced maternal age (2), second-opinion polydactyly (4), family history of polydactyly (1), uncertain dates (5), and growth (1). The gestational ages at the times of sonographic diagnosis ranged from 17.5 to 34 weeks with all but one case being identified before 23 weeks. Prenatal identification included polydactyly of the upper limb (8), lower limb (4), and both upper and lower limbs (1). Postaxial polydactyly was seen in 12 patients and preaxial in one. Polydactyly was confirmed in all 12 cases in which follow-up was available. Karyotypes were normal in all five fetuses in which amniocentesis was performed. Ten of 12 fetuses were born alive, one died in utero at 34 weeks as a complication of severe pre-eclampsia and one died at term as a result of a cord accident. No surviving neonate had any other identifiable malformation or suspected karyotypic abnormality. In conclusion isolated polydactyly identified by prenatal sonography is associated with good perinatal outcome.