Background: Twins have a higher mortality and morbidity than singletons and, among twins, the surviving co-twin of a fetus that dies in utero is particularly at risk. We did a cohort study to quantify mortality and serious morbidity in co-twin survivors of fetuses that died in utero.
Methods: We collected data of all registered twin births in England and Wales between 1993 and 1995 in which one twin was registered as having died in utero. Copies of all death certificates of these fetuses and death certificates of live-born co-twins of fetuses that died in utero were obtained from the Office for National Statistics. A questionnaire was sent to the general practitioners of all surviving co-twins to find out if the child had any disability.
Findings: There were 434 fetal death/live-birth same-sex twin pairs. Among the live births, there were 59 neonatal deaths, seven postneonatal deaths (first 28 days), and five infant deaths (<1 year). In three of the five deaths, the cause of death was cerebral palsy. Ten of the children who survived infancy were lost to follow up. Responses were received from general practitioners for 241 of 353 survivors (68% response). Of the 241 respondents, 23 had cerebral palsy and 28 had other cerebral impairment. Among the children who survived to infancy, the prevalence of cerebral palsy was 106 (95% CI 70-150) per 1000 and prevalence of other cerebral impairment was 114 (80-160) per 1000. There were 163 fetal death/live-birth different-sex twin pairs. Of the live births, 13 died in the neonatal period and four were lost to follow up. Of the 146 survivors, responses were received from the general practitioners for 102 (70% response). Three of the 102 had cerebral palsy and 12 had other cerebral impairment. The prevalence of cerebral palsy was 29 (95% CI 6-83) per 1000 and of other cerebral impairment 118 (62-196) per 1000 infant survivors.
Interpretation: The live-birth co-twin of a fetus that died in utero is at increased risk of cerebral impairment, the overall risk is 20% (95% CI 16-25). The gestational-age-specific prevalence of cerebral palsy after fetal death of the co-twin is much higher than that reported for the general twin population.