Should the interval between doses of antenatal corticosteroids be shortened in certain cases? Factors predicting preterm delivery < 48 h from presentation

Purpose: Treatment with antenatal corticosteroids (ACS) to women at risk for preterm birth (PTB) is associated with a reduction in adverse neonatal outcomes. Obstetricians occasionally shorten the interval between the doses of steroids if delivery is predicted to occur before ACS are fully administered. In this study, we aimed to investigate predicting factors to identify patients that will deliver prematurely, less than 48 h from presentation. Methods: The computerized medical files of all PTBs (< 34 weeks) were reviewed. Maternal demographics, pregnancy and delivery characteristics were compared between PTB that occurred < 48 h vs. > 48 h from triage presentation. Results: In total, 494 PTB cases were included: 302 women in the study group (PTB < 48 h) and 192 women in the control group (PTB > 48 h). No significant differences were found in demographic characteristics between the groups. At presentation, the study group had higher rates of uterine contractions (p < 0.001) and cervical length < 25 mm (p < 0.001) as well as a higher rate of non-reassuring fetal (NRFHR) monitor (p < 0.001). In contrast, the control group presented with higher rates of preeclampsia (p = 0.003) and preterm premature rupture of membranes (p = 0.038). In multivariable analysis, all of the above factors remained significant after controlling for background confounders. Conclusions: Various factors at presentation can predict delivery < 48 h. These factors can be used to predict patients to whom the ACS interval should be shortened. Future prospective studies should investigate the effect of this shortening on neonatal outcomes.