Circulatory effects of antenatal betamethasone therapy in low birthweight infants

We read with great interest the paper of Vural et al1 on the cardiac effects of single course antenatal betamethasone in preterm infants. In line with the observations of Dimitriou et al2 on the effect of betamethasone on neonatal renal function, there is still need to further document the impact of antenatally administered steroids on various extrapulmonary outcome variables such as cardiovascular stability.

We therefore would like to report on the use of dopamine in the first week of life in a cohort of 282 consecutively admitted low birthweight (LBW) infants—that is, <1500 g—of whom 243 survived until discharge. Our algorithm to initiate dopamine has recently been described.3

Data on antenatal betamethasone were not retrieved in six cases, resulting in observations on 237 LBW survivors. The clinical characteristics of the LBW infants either treated (n  =  178) or not (n  =  59) before birth with betamethasone can be summarised as follows (betamethasone/no betamethasone): number  =  178/59; mean (range) gestational age (weeks)  =  29 (24–34)/30 (24–35) (NS); mean (SD) birth weight (g)  =  1142 (272)/1062 (303) (NS); mean (range) CRIB score  =  2 (0–13)/2 (0–13) (NS); inotropic agents before day 7  =  38%/46% (NS); mean (range) duration (hours) of inotropic agents in first week when all survivors are included  =  0 (0–168)/0 (0–144) (NS), and when only LBW infants treated with inotropic agents are included  =  50 (4–168)/56 (8–144) (NS).

In brief, we were not able to find any difference in the administration or duration of administration of inotropic agents in the first week of life in LBW infants.

There is still uncertainty about the effect of prenatal steroids on various extrapulmonary outcome variables. As the positive effect of maternal administration of steroids on neonatal respiratory distress syndrome has been repeatedly demonstrated, a randomised controlled trial approach to assess the effect of prenatal steroids on these extrapulmonary outcome variables is no longer ethical or feasible. However, prospective collection of these variables, as was done by both groups mentioned above, is still of clinical relevance, especially if we take into account that the large randomised controlled trial studies were performed in the 1980s and 1990s and therefore potentially only in part reflect the populations admitted to our present day units.