Twins and cerebral palsy.

In a national follow-up study of twin births, monozygous compared with dizygous twins were at significantly increased for both to die in utero, one to die in utero and the co-twin to die in infancy, or both to be livebirths but both die in infancy. The prevalence of cerebral palsy among survivors of a co-twin fetal death was 80.2 and other cerebral impairment was 107.0 per 1000. Many apparently singleton cases of cerebral palsy and impairment may be due to fetal death of a twin that has not been recognized or has been recognized but not registered.