According to follow-up from a randomised trial, the use of a single repeat dose of antenatal betamethasone in women who remain undelivered does not influence physical growth or neurodevelopment at two years of age.

The authors note that a single course of antenatal corticosteroid given 7 days to 24 hours decreases the risk of respiratory distress syndrome (RDS) and reduces mortality.  Non-randomised studies suggested that weekly repeated doses in women who remained undelivered after the initial single course may improve respiratory outcome, but decreases foetal growth and may impair neurodevelopmental outcome. 

In a previous prospective placebo-controlled study, they evaluated the use of a single repeat course of betamethasone (12mg) in women with imminent delivery before 34 gestational weeks who remained undelivered for >7 days after a single course of antenatal BM. This was found to neither decrease foetal growth nor improve the outcome of preterm infants during the first hospitalisation, compared with placebo. 

In this paper they report on the two-year outcomes from 259 (82%) of the surviving infants from the trial, who underwent neurological and psychometric examinations and a speech evaluation at a corrected age of two years.  The rate of survival without severe neurodevelopmental impairment was similar in both groups (98% in the betamethasone group and 99% in the placebo group) and there was no difference in growth, rates of re-hospitalisation, or risk of cerebral palsy.

The authors conclude that “a single repeat dose of antenatal [betamethasone] had no detectable effect on growth or neurodevelopmental outcome at the age of 2 years. One or two repeat doses of antenatal [betamethasone] appear to be beneficial in reducing acute pulmonary morbidity, when the premature birth can be delayed at least 24 h after the steroid. More follow-up studies are needed before a recommendation is feasible.”