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225: Is it safe to perform vacuum extraction in neonates under 2500 grams?

      Objective

      Low birth weight (LBW) is relative contraindication for vacuum extraction (VE), although evidence regarding the safety of the procedure are controversial. Thus, we aimed to determine the risk for VE-associated birth trauma in a large cohort.

      Study Design

      Retrospective cohort study of singleton gestations, with birth weights of 2000-3500 grams, no anomalies, 34+0/7 weeks of gestation and above, who underwent VE (2007-2014). Pregnancy outcomes were compared between the study group (2000-2499 grams) and two control groups (1: 2500-2999 grams and 2: 3000-3500 grams). The sample sizes needed for the study and control groups to detect 2-fold increase in the baseline complication rate (4%) with β=0.8 and α=0.95 were 245 and 4,396 respectively. Primary outcome was defined as a composite outcome of birth injuries, and secondary outcome as a composite outcome of different perinatal outcomes (Table).

      Results

      Out of 62,102 deliveries, 5,064 met the inclusion criteria. Overall, 269 (5%) deliveries were included in the study group and 4,795 in both control groups. The groups differed significantly in gestational age, rates of mild and severe PET, induction of labor, meconium stained amniotic fluid and indication for VE and PPH (Table). Univariate analysis revealed an increase in the rate of complications related to birth weight and gestational age such as hypoglycemia, RDS, IVH, sepsis and jaundice. Nonetheless, no significant differences were detected regarding the primary composite birth injuries (study group vs. 2501-3000g: p=0.74, study group vs. 3001-3500g: p=0.18). Multivariable logistic regression model accounting for confounders yielded similar result (aOR 1.33, 95% CI 0.55-3.24, p=0.53).

      Conclusion

      Based on the power analysis and the results, we may conclude that birth weight of 2000-2499 grams is not a risk factor for traumatic birth injuries during vacuum extraction.
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