Cornelia de Lange syndrome (CdLS) should be considered in any fetus with growth restriction in addition to limb or craniofacial abnormalities, with or without a congenital heart defect. Classic sonographic signs of CdLS include increased first-trimester nuchal translucency, intrauterine growth restriction, short or absent upper limbs, absent digits, fifth finger clinodactyly, syndactyly, radial hypoplasia, microcephaly, micrognathia, and congenital heart defects. However, unless there is a previous family history of CdLS, prenatal diagnosis is unlikely to be possible, and the diagnosis will have to be made after postnatal examination. In families with a history of CdLS where a mutation has been identified, prenatal diagnosis by chorionic villus sampling or amniocentesis is likely to be available. Normal first-trimester nuchal translucency, normal first-trimester or second-trimester maternal serum pregnancy-associated plasma protein A, or a normal second-trimester ultrasound examination in a fetus with a family history of CdLS is largely reassuring but cannot entirely rule out recurrence. Because most cases of CdLS are de novo, couples who do not have CdLS but have a previously affected child have a 1.5% risk of recurrence. If a parent of the affected child has CdLS, there is a 50% chance of a recurrence for each pregnancy.