Analysis of limb reduction defects in babies exposed to chorionic villus sampling.

In 1991 we reported a cluster of babies with limb abnormalities and suggested that chorionic villus sampling (CVS) was aetiologically associated with these defects. To address the issue more objectively, we have assessed reported limb reduction defects in 75 babies exposed to CVS in utero. 13 babies had an absent limb or a defect through the humerus or femur; 9 had defects through the radius or tibia; 22 defects of the carpus, tarsus, metacarpus, or metatarsus; 25 defects of the digits; and 6 defects of the terminal phalanx or nail only. There was a strong correlation between the severity of the defects and the duration of gestation when CVS was done. The median gestational age at CVS ranged from 56 (range 49-65) postmenstrual days for the most severe category to 72 (51-98) days for the least severe. The relation was seen for both isolated limb defects and for cases with oromandibular-limb hypogenesis syndromes. This relation is further evidence that CVS has an aetiological role in some limb reduction anomalies.