The impact of maternal obesity on outcomes of vacuum-assisted vaginal birth: a retrospective cohort study with emphasis on shoulder dystocia and severe perineal lacerations
DOI:
https://doi.org/10.37800/RM.2.2026.720Keywords:
maternal obesity, fetal vacuum extraction, shoulder dystocia, perineal tears, fetal macrosomiaAbstract
Relevance: Maternal obesity (BMI ≥30 kg/m²) is a significant risk factor for obstetric complications. However, its impact on the outcomes of vacuum-assisted births in Central Asia, including Kazakhstan, with a high prevalence of obesity and macrosomia, has been poorly studied.
The study aimed to assess the impact of maternal obesity on the incidence of shoulder dystocia, severe perineal lacerations, and other complications during vacuum extraction of the fetus.
Materials and Methods: A retrospective cohort study of 22,456 full-term (≥37 weeks) singleton vaginal deliveries at Perinatal Center No. 1 in Karaganda (Kazakhstan) in 2021-2025. Of them, 19.8% deliveries were completed with vacuum extraction. Pre-pregnancy BMI was classified according to the WHO categories. Multivariable logistic regression, propensity score matching, and interaction analysis (BMI × macrosomia × vacuum extraction) were used.
Results: Grade I-III obesity was detected in 28.4% of women and was more common in the vacuum extraction group. In grade II-III obesity, the risk of shoulder dystocia and grade III-IV perineal tears increased more than threefold compared to a normal BMI, especially in the presence of fetal macrosomia. An increased incidence of postpartum hemorrhage and brachial plexus injury was also noted.
Conclusion: Maternal obesity, especially a BMI ≥35 kg/m², is an independent determinant of severe complications during vacuum extraction and should be considered when choosing a delivery method and developing preconception weight loss programs in Kazakhstan.
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Copyright (c) 2026 D.E. Omertayeva, М.М. Мугазов, А.М. Съездова, А.С. Савлимова, А.А. Шайзадина, К.Т. Шыхалиева, Ж.К. Жарова
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