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Clinical Obstetrics

Poster Session 2

(387) Duration of Third Stage of Labor and Maternal Hemorrhagic Adverse Outcomes

Tuesday, February 13, 2024
3:30 PM – 5:00 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective: ACOG Practice Bulletin on postpartum hemorrhage (#183) notes, that the third stage of labor (TSL) is associated with morbidity, although this threshold is not well established. Our objective was to identify the association between the duration of the TSL and composite maternal hemorrhagic adverse outcomes (CMHAO).

Study Design: A retrospective cohort study of all singleton vaginal deliveries (VD) between March 2020 and Feb 2022 at a single Level IV center. Individuals with an unrecorded length of the TSL were excluded. We divided the cohort into 5-minute intervals after delivery of the newborn. Each 5-minute interval group was compared to all cases with a shorter TSL. Using Poisson regression, we evaluated whether TSL was associated with CMHAO, which consisted of blood loss ≥ 1000 mL, use of uterotonics, mechanical tamponade, surgical techniques for atony, transfusion, venous thromboembolism, intensive care unit admission, hysterectomy, or death. We did a sensitivity analysis of TSL among term (≥ 37 wks) and preterm VD.

Results: Of the 4,599 consecutive VD in the study period 4,513 (98%) met inclusion criteria, and of those, 777 (17%) had CMHAO. After 20 min, each addition of 5 min to TSL was associated with a significant increase in the CMHAO rate. Compared to TSL < 20 min, individuals with an interval of 20-24 min had higher rates of CMHAO (aRR 2.85, 95% CI 1.64-4.94). Likewise, CMHAO differed significantly when comparing 24-29 min and < 24, and ≥ vs. < 30 min (Fig). A sensitivity analysis of term VD noted a similar pattern: compared to less than 20 minutes, the 20-24 min interval was associated with a higher rate of CMHAO (aRR 2.63, 95% CI 1.31-5.30), as were the longer intervals. Due to infrequent outcomes, we were unable to perform a separate sensitivity analysis for preterm births.

Conclusion: Among singleton vaginal deliveries, third stage duration of > 20 min, compared to < 20 min, was associated with significantly higher likelihood of hemorrhagic adverse outcomes. If confirmed in other population, guidelines on the duration of third stage of labor and associated morbidity may need revision.