Purpose: The administration of a single-course antenatal corticosteroid treatment is recommended for pregnant women between 24 and 34 weeks with risk of premature birth. The maximum effect is achieved when antenatal corticosteroids are administered between 24h and 7 days before delivery. The objective of this study was to evaluate the occurrence of birth within seven days of corticosteroid therapy in major obstetric situations with risk of preterm birth.
Methods: Retrospective cohort study including 209 pregnant women hospitalized in risk of preterm delivery, submitted to corticosteroid therapy for fetal lung maturation. The study was carried out between January 2012 and March 2014 at a university hospital. Main outcome measure was the number of women who delivered within 7 da ys after antenatal corticosteroid administration. Two groups were defined according to the reason for starting corticosteroids: threatened preterm labour (Group APPT) and other indications for corticosteroid therapy (Group RPPT). A Kaplan-Meier survival analysis was performed and a p value <0.05 was considered statistically significant.
Results: 46.4% (n=97) of pregnant women gave birth in the seven days following corticosteroid administration. Delivery within 7 days occurred more frequently on group 2 in comparison to group 1 (57.3 versus 42.4%; p=0.001). There is a statistically significant difference between the survival curve for groups 1 and 2, with a hazard ratio for delivery within 7 days 1.71 times higher for group 2 (95%CI 1.23-2.37; p<0.001).
Conclusion: It can be concluded that the probability of an event (birth within 7 days after corticosteroids) is smaller in the group of pregnant women admitted in the context of threatened preterm labor than for other indications. The use of corticosteroids in pregnant women admitted for suspected preterm labor should be subject to rigorous clinical evaluation.