A case-control study of vanishing twin as a risk factor for cerebral palsy.
Twin Res, 6 (2):
83--84 (April 2003)DOI: 10.1375/136905203321536191
Abstract
It has been hypothesized that cerebral palsy of unknown etiology is the result of the death of an unrecognized co-twin--a vanishing twin--in early gestation. We conducted a case-control study of vanishing twin as a risk factor for cerebral palsy of unknown etiology in women who had an obstetric ultrasound during pregnancy. Among mothers of cases, one of 86 had evidence of a vanishing twin on ultrasound, as compared to two of 381 control mothers (odds ratio OR 2.2, 95\% confidence interval CI 0.2-24.8; p = 0.5). Bleeding in early pregnancy, which may indicate the loss of a co-twin, was reported by 14 case mothers and 46 control mothers (OR 1.6, 95\% CI 0.8-3.0; p = 0.3). On the basis of results presented here, the vanishing twin syndrome is unlikely to account for a high proportion of cases of cerebral palsy, but there is insufficient statistical power to draw firm conclusions.