Objective: To examine the effect of antenatal indomethacin (AI) exposure on the incidence, response to postnatal indomethacin (PI), and need for surgical ligation of patent ductus arteriosus (PDA) in preterm infants.
Methods: We performed a retrospective matched cohort study of infants born at < or = 30 weeks' gestation after exposure to AI administered because of preterm labour. Control subjects were infants unexposed to AI but with similar gestational age and birth weight. We compared the incidence of PDA, response to treatment with PI, and surgical PDA ligation rate between the two groups.
Results: There was no difference in the incidence of PDA between AI infants (67.6%) and control subjects (66.6%). Only 22 of 54 (41%) infants in the AI group responded to PI therapy for symptomatic PDA closure, compared to 34 of 52 (65%) infants in the control group (P = 0.012). Thirty-two (59%) infants in the AI group required surgical PDA ligation after indomethacin therapy, compared with 18 infants in the control group (35%) (P = 0.01). Multivariate logistic regression analysis showed that AI exposure was independently associated with surgical ligation of PDA (adjusted odds ratio 3.07; 95% CI 1.46 to 6.45).
Conclusion: In infants born preterm (< or = 30 weeks) with a PDA, antenatal exposure to indomethacin was associated with an increased rate of therapeutic failure of PI and an increased rate of surgical PDA ligation compared with controls without such antenatal exposure.