This review shows that a repeat dose of prenatal corticosteroids given to women who remain at risk of an early birth after an initial course of prenatal corticosteroids helps the baby's lungs and reduces serious health problems in the first few weeks of life.
Infants born preterm (before 37 weeks' gestation) are at risk of difficulty breathing and lung disease because their lungs are not fully developed. Woman at risk of preterm birth include those with ruptured membranes, antepartum haemorrhage, preterm labour, cervical incompetence, pre-eclampsia or multiple pregnancy. Preterm babies who survive the early weeks of life are also at risk of long-term neurological disabilities such as epilepsy and cerebral palsy. A single course of corticosteroids, given to women who may give birth early, helps develop the baby's lungs. This benefit does not last beyond seven days. This review of 10 randomised controlled trials, involving more than 4730 women who remained at risk of early birth more than seven days after an initial course of corticosteroids and 5650 babies between 23 and 34 weeks' gestation showed that repeat dose(s) of prenatal corticosteroids reduced the risk of the baby having breathing difficulties and serious health problems in the first few weeks of life. Some of the trials showed that the baby may be smaller at birth but not if adjusted for gestational age nor by the time of hospital discharge. In four trials that followed up the babies to early childhood, no long-term benefits or harms were seen at 18 months to two years' corrected age. Further research is needed on the long-term benefits and risks for the woman and baby, which should include later child health, growth and development.
Repeat prenatal corticosteroid treatment could increase the risk of infection and suppress pituitary-adrenal function for the mother and her baby. For the women, there was no increase in infectious morbidity of chorioamnionitis or puerperal sepsis, and the likelihood of a caesarean birth was unchanged.
Betamethasone was the only corticosteroid evaluated. It is uncertain whether the effects seen for betamethasone would be the same for dexamethasone.