Predicting Postpartum Hemorrhage After Vaginal Birth by Labor Phenotype

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Reproductive Health

Background:

• Postpartum hemorrhage (PPH) significantly contributes to maternal morbidity and mortality worldwide.
• Predictive models for PPH are essential for quality improvement in obstetric care.
• Identifying labor process phenotypes can refine PPH risk assessment.

Purpose of the Study:

• To identify distinct labor process phenotypes in women undergoing vaginal birth.
• To estimate the likelihood of PPH within each identified labor phenotype.
• To analyze the association of maternal and fetal characteristics with PPH risk across different labor phenotypes.

Main Methods:

• Utilized the Consortium for Safe Labor dataset (2002-2008) for term, singleton, vaginal births.
• Applied latent class analysis using 16 variables describing labor and birth processes.
• Identified five distinct labor process phenotypes based on interventions, duration, and complications.

Main Results:

• A total of 4.72% of 24,729 births resulted in PPH.
• Phenotypes with complicated prolonged labors (spontaneous or induced) had the highest PPH rates (8.0% and 12.0%).
• Lower PPH rates (3.8%-3.9%) were observed in women with shorter admission durations after spontaneous labor onset.
• The majority of PPH cases (75%) occurred in phenotypes with fewer labor complications.
• Nulliparous women, Black women, and Hispanic women exhibited higher odds of PPH.
• Within phenotypes, increased PPH odds were linked to nulliparity, macrosomia, hypertension, and depression.

Conclusions:

• Women in lower-risk labor phenotypes experiencing PPH were more likely to be nulliparous, a person of color, or have hypertension.
• Labor phenotypes provide a framework for understanding PPH risk beyond general characteristics.
• Targeted interventions for PPH prevention may be enhanced by considering labor process phenotypes and associated demographic factors.