Importance  

Controversies persist about management of the ductus arteriosus by nonsteroidal anti-inflammatory drugs in extremely preterm infants. Acetaminophen (paracetamol) appears to be a promising alternative with possibly fewer adverse effects.

Objective  

To evaluate whether prophylactic intravenous acetaminophen started within 12 hours of birth increases survival without neonatal severe morbidities at 36 weeks’ postmenstrual age.

Design, Setting, and Participants  

A double-blind, randomized, placebo-controlled clinical trial was conducted among preterm infants born between 23 weeks 0 days and 28 weeks 6 days of gestation in 43 neonatal intensive care units of 14 European countries between October 2020 (October 2021 for infants born at 23-26 weeks’ gestation, after the phase 2 study identified the optimal dose of acetaminophen) and April 2024. Data analysis was conducted from January to June 2025.

Intervention  

In the acetaminophen group, patients born at 27 to 28 weeks’ gestation received a 20-mg/kg loading dose of acetaminophen followed by 7.5 mg/kg every 6 hours for 5 days, and patients born at 23 to 26 weeks’ gestation received a 25-mg/kg loading dose of acetaminophen followed by 10 mg/kg every 6 hours for 5 days. In the placebo group, isotonic sodium chloride was administered.

Main Outcomes and Measures  

The primary outcome was survival without neonatal morbidity evaluated at 36 weeks’ postmenstrual age. The secondary exploratory outcome was ductus arteriosus closure, assessed by echocardiography on day 7.

Results  

A total of 778 patients (median [IQR] gestational age, 26 [25-27] weeks; 375 [48.2%] female) were included in the study, with 391 in the acetaminophen group and 387 in the placebo group. Survival without severe morbidities at 36 weeks’ postmenstrual age occurred in 259 infants (66.2%) in the acetaminophen group and 246 (63.6%) in the placebo group (absolute risk difference [ARD], 2.7 [95% CI, −4.0 to 9.3] percentage points; relative risk [RR], 1.04 [95% CI, 0.94 to 1.16]). The ductus arteriosus was considered closed on day 7 in 264 of 371 infants (71.2%) assigned to acetaminophen and 191 of 366 infants (52.2%) assigned to placebo (ARD, 19.0 [95% CI, 12.0 to 25.7] percentage points; RR, 1.36 [95% CI, 1.21 to 1.53]). In the safety analysis, adverse events were not different except for a higher cholestasis rate in the acetaminophen group (25 of 392 infants [6.4%]) vs the placebo group (10 of 386 infants [2.6%]) (ARD, 3.8 [95% CI, 0.9 to 6.9]) percentage points.

Conclusions and Relevance  

This study found that prophylactic acetaminophen treatment for patent ductus arteriosus did not increase survival without neonatal morbidities.