Objective: To assess the long-term effects of in utero exposure to magnesium sulphate for children whose mothers had pre-eclampsia.
Design: Assessment at 18 months of age for children whose mothers were recruited to the Magpie Trial (recruitment 1998-2001 ISRCTN 86938761), which compared magnesium sulphate with placebo.
Setting: Follow-up of children born at 125 centres in 19 countries across five continents.
Population: A total of 6922 children were born to women randomised before delivery at follow-up centres. Of these, 2271 were not included for logistic reasons and 168 were excluded (101 at a centre where <20% were contacted, 40 whose death or disability was due to a problem at conception or embryogenesis and 27 whose parent/s opted out). Therefore, 4483 children were included in follow-up, of whom 3283 (73%) were contacted.
Methods: Assessment by questionnaire, with interview and neurodevelopmental testing of selected children.
Main outcome measures: Death or neurosensory disability at age of 18 months.
Results: Of those allocated magnesium sulphate, 245/1635 (15.0%) were dead or had neurosensory disability at 18 months compared with 233/1648 (14.1%) allocated placebo (relative risk [RR] 1.06, 95% CI 0.90-1.25), and of survivors, 19/1409 (1.3%) had neurosensory disability at 18 months compared with 27/1442 (1.9%) (RR 0.72, 95% CI 0.40-1.29). There were no substantial differences in causes of death or in the risk of individual impairments or disabilities.
Conclusions: The lower risk of eclampsia following prophylaxis with magnesium sulphate was not associated with a clear difference in the risk of death or disability for children at 18 months.