Zhang C, et al. – The impact of maternal pre–pregnancy obesity on the risk of shoulder dystocia is assessed in this study. This meta–analysis proposes that maternal pre–pregnancy obesity is related to increased risk of shoulder dystocia.

Methods

• For this study, they designed a meta–analysis.
• They searched PubMed and Web of Science database for all relevant studies up to 5 August 2016 and reviewed the reference lists of identified articles.
• Observational studies that explored the relationship between pre–pregnancy obesity and the risk of shoulder dystocia were included.
• In this meta–analysis, a total of 20 articles involving 2153898 participants were included.
• A random effects model was used to calculate the pooled relative risks (RRs) with 95% confidence intervals (CIs).

Results

• For obese versus non–obese, the pooled RR of shoulder dystocia was 1.63 (95% CI 1.33–1.99).
• The outcomes remained significant in the cohort studies (RR = 1.59, 95% CI 1.28–1.97) and case–control studies (RR = 1.92, 95% CI 1.03–3.57).
• With regard to the subgroup of continents, there was significant relationship amongst obesity and the risk of shoulder dystocia in Europe (RR = 1.51, 95% CI 1.18–1.92) and Asia (RR = 2.59, 95% CI 1.15–5.83).
• The outcome from the sensitivity examination for studies adjusted for gestational diabetes was significant (RR = 1.61, 95% CI 1.05–2.47).
• The pooled RRs for obesity classes I, II and III versus non–obese were 1.29 (95% CI 1.06–1.57), 1.94 (95% CI 1.26–2.98) and 2.47(95% CI 1.56–3.93), respectively.