Background: Roughly 10% of newborns need help to complete the transition of birth. For these infants, international guidelines recommend supporting them using a 4-step procedure (A to D). Step A is an assessment time, which includes eight tasks and finishes by starting the positive pressure ventilation (PPV), if necessary (step B). The guidelines changed in 2015 and the allotted time was raised from 30 to 60 seconds for step A completion. This study aimed to assess if the reduced time constraint in step A could have an impact on 1st-year pediatric residents' performance to complete step A and if could lead to later initiation of step A., Methods: Using video recordings of standardized neonatal scenarios over 6 years (3 before the change and 3 after), we assessed the ability of 1st-year pediatric residents of the Paris region to complete step A and initiate PPV in the allotted time in each period. Among the sessions, including at least five scenarios we evaluated all the PPV required scenarios executed for the first time by a dyad of 1st-year pediatric residents., Results: Among 52 sessions, we included 104 scenarios (25 sessions and 50 scenarios before the change and 27 sessions and 54 scenarios after). PPV started roughly at 1-minute resuscitation in both periods, but completion of the tasks before PPV-start was significant. Only 12% of the dyad of residents executed the eight tasks before PPV initiation in the first period versus 54% in the second period (p < 0.0001). Additionally, the completion of the eight tasks of step A was significantly better during the second period (6 [6-7] vs. 8 [7-8] p < 0.001)., Conclusions: These results could suggest that a reduced time constraint for step A imposed by the new Guidelines was associated with better performance.