RESUMO
AIM: This study aims to examine the association between body mass index (BMI) and mode of delivery, progression of labour, and intrapartum interventions. METHODS: This was a retrospective matched cohort study including Class III obese (BMI ≥40 kg/m2 ) and normal BMI (BMI <25 kg/m2 ) women planning a vaginal birth who had a live, singleton delivery from January 2015 to December 2018. Patients were matched (1:1) based on age, gestational age, parity, onset of labour and birth weight. The primary outcome was caesarean delivery (CD). Secondary outcomes were delivery outcomes, intrapartum management and interventions. Rates of each outcome were compared with matched analysis, and duration of labour with time-to-event analysis. RESULTS: We studied two groups of 300 pregnant women. The CD rate was significantly higher for obese women than the normal BMI cohort (19.3% vs 13.3%; risk ratio (RR) 1.43, 95% CI 1.02-1.98, P = 0.035). Cervical dilation prior to CD for failure to progress was slower in obese than normal BMI (0.04 vs 0.16 cm/h). The obese cohort had a longer duration of labour in those who underwent induction (13.70 vs 11.48 h, P = 0.024). Intrapartum intervention rates were higher for obese women, with significant differences in rates of fetal scalp electrodes (72.7% vs 22.7%, RR 3.20, 95% CI 2.58-3.99, P < 0.001), intrauterine pressure catheters (18.3% vs 0%, P < 0.001), epidural analgesia (44.0% vs 37.0%, RR 1.20, 95% CI 1.01-1.44, P = 0.040) and fetal scalp lactate sampling (8.0% vs 3.0%, RR = 2.67, 95% CI 1.33-5.33, P = 0.004). CONCLUSION: Class III obesity is associated with an increased risk of CD and intrapartum interventions.
RESUMO
BACKGROUND: Induction of labour is one of the most common obstetric interventions globally. Balloon catheters and vaginal prostaglandins are widely used to ripen the cervix in labour induction. We aimed to compare the effectiveness and safety profiles of these two induction methods. METHODS: We did an individual participant data meta-analysis comparing balloon catheters and vaginal prostaglandins for cervical ripening before labour induction. We systematically identified published and unpublished randomised controlled trials that completed data collection between March 19, 2019, and May 1, 2021, by searching the Cochrane Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, and PubMed. Further trials done before March 19, 2019, were identified through a recent Cochrane review. Data relating to the combined use of the two methods were not included, only data from women with a viable, singleton pregnancy were analysed, and no exclusion was made based on parity or membrane status. We contacted authors of individuals trials and participant-level data were harmonised and recoded according to predefined definitions of variables. Risk of bias was assessed with the ROB2 tool. The primary outcomes were caesarean delivery, indication for caesarean delivery, a composite adverse perinatal outcome, and a composite adverse maternal outcome. We followed the intention-to-treat principle for the main analysis. The primary meta-analysis used two-stage random-effects models and the sensitivity analysis used one-stage mixed models. All models were adjusted for maternal age and parity. This meta-analysis is registered with PROSPERO (CRD42020179924). FINDINGS: Individual participant data were available from 12 studies with a total of 5460 participants. Balloon catheters, compared with vaginal prostaglandins, did not lead to a significantly different rate of caesarean delivery (12 trials, 5414 women; crude incidence 27·0%; adjusted OR [aOR] 1·09, 95% CI 0·95-1·24; I2=0%), caesarean delivery for failure to progress (11 trials, 4601 women; aOR 1·20, 95% CI 0·91-1·58; I2=39%), or caesarean delivery for fetal distress (10 trials, 4441 women; aOR 0·86, 95% CI 0·71-1·04; I2=0%). The composite adverse perinatal outcome was lower in women who were allocated to balloon catheters than in those allocated to vaginal prostaglandins (ten trials, 4452 neonates, crude incidence 13·6%; aOR 0·80, 95% CI 0·70-0·92; I2=0%). There was no significant difference in the composite adverse maternal outcome (ten trials, 4326 women, crude incidence 22·7%; aOR 1·02, 95% CI 0·89-1·18; I2=0%). INTERPRETATION: In induction of labour, balloon catheters and vaginal prostaglandins have comparable caesarean delivery rates and maternal safety profiles, but balloon catheters lead to fewer adverse perinatal events. FUNDING: Australian National Health and Medical Research Council and Monash Health Emerging Researcher Fellowship.