Limb Defects After Chorionic Villus Sampling

Obstetrics & Gynecology, Fon-Jou Hsieh, Ming-Kwang Shyu, et al, Vol. 85, No. 1, 84-87.

Chorionic villus sampling (CVS) has become a widely-used technique for prenatal genetic diagnosis, even though it was still considered experimental as recently as 1992. The test is used to identify chromosome and biochemical conditions such as Tay-Sachs disease, the sex of the fetus and certain inherited conditions. Although it was at first hailed as a very safe procedure, reports soon began to surface about CVS possibly causing limb defects in babies.

This study from Taiwan surveyed the incidence of limb defects during 1991, in mothers who were and were not exposed to CVS. Despite several previous reports and letters to peer-reviewed journals concerning an association between limb defects and CVS, there has still been argument over such a link, with some claiming that the limb defects noted in previous studies were part of certain syndromes unconnected to CVS. For this reason, the Taiwan study included a control group.

The results of the study are clear. The incidence of limb defects, especially the severe types, was increased after CVS, to a degree that was statistically significant. In addition, the spectrum of limb defects with CVS exposure was more severe than the limb defects seen in the general population. CVS-exposed babies had missing or fused fingers or toes, cleft lips, missing or shortened arms or legs and some facial defects.

The authors stop short of recommending that CVS not be performed and instead support the idea of performing CVS only after 10 full gestational weeks. They give no reason for recommending the continued use of CVS, but they do cite a report that suggests that limb defects produced from CVS after 9.5 weeks tend to involve missing or abnormal fingers and toes rather than arms or legs.

Ina May Gaskin.

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By Ina May Gaskin

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