One of the most commonly used prenatal tests for genetic defects -- CVS -- may itself cause defects in a baby's limbs, according to a study being published today.
The study said 1 percent of CVS-tested babies at a Chicago hospital were born with such defects as missing toes, fingers and fingernails. The finding prompted the federal government to call a special meeting last month of international birth defect experts.
Although the experts have made no recommendation as yet, several are suggesting that pregnant women be informed about limb abnormalities reported in the last year in CVS-tested babies in Chicago and elsewhere.
The Chicago hospital where the latest study originated, Humana Hospital-Michael Reese, has already dropped the CVS (chorionic villus sampling) test.
The hospital found four abnormalities among 395 babies tested.
Although amniocentesis is still used twice as frequently to detect genetic defects such as Down's syndrome, women increasingly are turning to CVS because it can be used as early as 12 weeks, compared with 16 or 17 weeks for amniocentesis. The earlier results are often critical to women making the difficult decision about whether to abort an abnormal fetus.
But there was criticism raised yesterday about the Chicago study as well as concern that it might unduly frighten parents into dropping a valuable prenatal test.
Laird Jackson, director of medical genetics at Thomas Jefferson University Hospital in Philadelphia, one of the nation's pioneers in the CVS procedure, said the hospital had not found an increased risk of limb defects after performing more than 10,000 CVS tests.