Late preterm delivery has a distinctive second-stage duration and characteristics

Area of Science:

• Obstetrics and Gynecology
• Neonatal Medicine
• Perinatal Research

Background:

• Late preterm neonates (34.0-36.6 weeks gestation) face higher risks of morbidity and mortality.
• Current labor curves do not specifically address late preterm births.
• The optimal duration of the second stage of labor for late preterm births remains undefined.

Purpose of the Study:

• To compare and characterize the duration of the second stage of labor between late preterm and term births.
• To identify factors influencing the second stage of labor duration in these groups.

Main Methods:

• Retrospective study analyzing 962 late preterm and 9476 term vaginal deliveries (May 2014-May 2021).
• Comparison of second stage duration, maternal characteristics, labor interventions, and neonatal outcomes.
• Multivariate Cox regression analysis to identify influencing variables.

Main Results:

• The second stage of labor was significantly shorter in late preterm births (1.08 hours) versus term births (1.49 hours).
• This difference was more pronounced in nulliparous women.
• Late preterm births had lower rates of operative vaginal delivery and perineal lacerations but higher rates of chorioamnionitis and NICU admission.

Conclusions:

• Vaginal delivery during the late preterm period is characterized by a significantly shorter second stage of labor.
• Optimal duration of the second stage of labor needs further investigation for late preterm neonates.
• Understanding these differences is crucial for managing labor and improving neonatal outcomes.