Vacuum extraction outcomes in primiparas delivered with an induction of labor

Abstract

Induction of labor (IOL) has become a common practice in the western world although it might prolong labors and potentially increase interventions. Vacuum extraction (VE) might result in obstetrical complications due to birth trauma. We aimed to evaluate the impact of an IOL on outcomes of primiparas delivered by VE. A retrospective cohort including primiparas with a singleton pregnancy ≥34w delivered by VE. We estimated delivery complications among deliveries that started with an IOL, compared to deliveries with a spontaneous onset of labor (SO). Included 2,975 deliveries, 1,048 (35.2%) with IOL and 1,927 (64.8%) with a SO. Comparing the basic characteristics between the groups: The rates of pre-gestational and gestational DM were higher in the IOL group (13.5% vs 8.2%, p< 0.001). Obesity rates (BMI >30kg/m2) were similar. Gestational age (GA) at delivery did not have a clinically significant difference (39.6 ± 1.4 in the IOL, 39.2± 1.3 in the SO, p< 0.001). Comparing labor characteristics: Epidural analgesia was more common in IOL (97.9% vs 90.7%, p< 0.001). Neonatal birthweight (BW) was higher in IOL (3210.7g ± 438.7 vs 3155.5 ± 417.3, p=0.001) and also the rates of BW ≥3700g (13.5% vs 8.4% p< 0.001). 2nd stage arrest (SSA) as the indication for VE was relatively common in the IOL group (29.8% vs 23%, p< 0.001), and rates of subgaleal hematomas (SGH) were higher (7.6% vs 4.4%, p< 0.001). Other maternal and neonatal complications: 3rd-4th degree perineal lacerations, blood loss, shoulder dystocia, clavicular fractures, Apgar scores, cord pH< 7.1 and NICU admission were comparable. Logistic regression found IOL as a risk factor for both SSA (aOR 1.3, 95%CI 1.1-1.5) and SGH (aOR 1.6, CI 1.2-2.2) when adjusting for the confounders of maternal age and BMI, GA, DM, epidural and neonatal BW. VE performed in deliveries that were induced were more likely to be performed due to SSA and complicated by increased rates of SGH which might be related to the VE indication. These outcomes can be incorporated into clinical decisions regarding IOL and mode of deliveryView Large Image Figure ViewerDownload Hi-res image Download (PPT)