Long-term impacts of antenatal corticosteroid exposure and preterm birth
Antenatal corticosteroids are recommended for women at risk of preterm birth before 35 weeks’ gestation for reducing the significant neonatal morbidity and mortality caused by preterm birth. The long-term impacts of both preterm birth and antenatal corticosteroids are incompletely understood. The aim of this work was to investigate the long-term health impacts of antenatal corticosteroids and of preterm birth. In a Cochrane systematic review, we showed that repeat doses of antenatal corticosteroids for women at ongoing risk of preterm birth after an initial course decreased respiratory distress syndrome and other serious infant outcomes compared with the initial course alone. No benefits or harms were identified at mid-childhood. We re-analysed data from the first randomised, placebo-controlled trial of antenatal corticosteroids using contemporary methods. Our findings were consistent with previously published results of reduced respiratory distress syndrome in the group randomised to antenatal betamethasone. We followed up the adult offspring of participants in this trial using a health questionnaire and routinely collected data. Of 1,218 infants born to 1,115 women, 424 participants were included at mean age 49.3 years (46% of survivors). Forty-six participants deceased prior to follow up had routinely collected data available. The findings indicated no clinically important long-term effects of antenatal corticosteroids. The prevalence of any of hypertension, dyslipidaemia, diabetes mellitus, prediabetes and gestational diabetes mellitus was not different between participants randomised to antenatal betamethasone or placebo. Age at first major adverse cardiovascular event was also not different between treatment groups. Other outcomes were similar between groups, including respiratory (primarily asthma), mental health, general health and social outcomes. These findings provide evidence for the long-term safety of antenatal corticosteroids. Preterm birth was associated with an increased risk of hypertension and no difference in risk of dyslipidaemia, diabetes or prediabetes but a lower risk of cardiovascular disease events at 50 years. The apparent paradox of elevated risk but fewer events implies that either traditional cardiovascular risk factors are not predictive of risk or that other protective factors are mitigating risk in this cohort.
Antenatal interventions, Antenaral corticosteroids, Long term follow up
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