What are the novel findings of this work?
In women with twin pregnancy, the risk of fetal loss following chorionic villus sampling (CVS) depends on a series of maternal and pregnancy characteristics and, to a lesser extent, on the procedure itself. The risk factors for spontaneous fetal loss are similar to those that lead to CVS being performed, and, in women with a high background risk of fetal loss, the risk of fetal loss following the invasive test could paradoxically be lower than if they did not have the invasive test, for the simple reason that prenatal diagnosis often converts spontaneous loss of a chromosomally abnormal fetus into pregnancy termination.
What are the clinical implications of this work?
The true procedure-related risk of fetal loss from CVS in twin pregnancy can be derived only by examining women with a low background risk of fetal loss, and in such women, the risk of fetal loss may increase by about 3.5% after CVS.