Background: Low dose aspirin is increasingly used during pregnancy, based on demonstrated reduction of risk for preeclampsia, preterm birth, and intra uterine growth retardation.
Objective: We aimed to assess the burden of hemodynamically significant patent ductus arteriosus (hs-PDA) in preterm infants exposed to aspirin in utero, and the response of aspirin- primed ductus to postnatal NSAIDs treatment.
Methods: We retrospectively reviewed the medical records of 21 PTI  born at GA<34 weeks, whose mothers were treated with aspirin during gestation and close to delivery and who were screened for PDA during the first 80 hours of life based on respiratory distress syndrome (RDS) severity and their need for positive pressure ventilation. These infants were compared with 42 preterm infants born before and after each study case, matched for gestational age, birth weight and antenatal steroid treatment. 
Results: We found significantly lower frequency of hs-PDA and higher rate of successful  pharmacological PDA closure after single course of ibuprofen treatment along with a significantly lower cumulative doses of ibuprofen in the study group. Furthermore, PDA closure was achieved significantly earlier in the study group ( day 4 vs 11, p = 0.02).In the control group, the advancement of enteral feeds was slower, and the  incidence of surgical ligation was higher, however these results did not reach significance, probably due to the small cohort used. 
No differences were found in long term neonatal outcomes (IVH, PVL, duration of  ventilation, BPD,  type 1 ROP, NEC, blood stream infection or death). 
Conclusions: No adverse events were associated with maternal aspirin treatment prior preterm delivery. Moreover, it seemed to reduce the incidence of hs-PDA and to increase infant responsiveness to postnatal medical treatment of PDA.

0077 - EFFECTS OF MATERNAL ASPIRIN TREATMENT ON PRETERM HEMODYNAMICALLY SIGNIFICANT PATENT DUCTUS ARTERIOSUS.