Does delayed vacuum-assisted delivery harbor greater maternal or neonatal complications?

To compare maternal and fetal outcomes between early (<2 h) and delayed (>2 h) vacuum extraction (VE) deliveries.

We performed a retrospective cohort study in a single, university-affiliated medical center (2014-2021). We included term singleton pregnancies delivered by VE, allocated into one of two groups according to second stage duration: <2 h or >2 h. Primary outcome was maternal composite adverse outcome (included chorioamnionitis, 3-4 degree lacerations, and postpartum hemorrhage [PPH]).

We included 2521 deliveries: 2261 (89.6%) with early VE and 260 (10.4%) with delayed VE. Study groups' characteristics were not different, except of parity. Maternal composite outcome almost reached a significance (P = 0.054) comparing between the groups. Comparing second stage length up to 2 h versus more, there was similar rate of advance maternal lacerations. However, extending the second stage to more than 3 h was associated with third degree lacerations compared to 2-3 h (9.8% vs 3%, P = 0.011). There were significantly more PPH events in the later VE group (P = 0.004), but the need for blood transfusions was similar. The rates of 5 min Apgar score ≤7 (P = 0.001) and umbilical artery pH <7.0 were significantly higher in group 2 compared with group 1. The effect was much more pronounced when second stage was >3 h. After conducting multiregression analysis, the results became insignificant.

Our study suggests that VE performed in the late second stage of labor, up to 3 h, is safe as VE performed in the early stages regarding maternal and neonatal outcomes. Extra caution is needed with extended second stage to more than 3 h.