C-sections linked to long-term risks and benefits

Compared to vaginal deliveries, caesarean deliveries are associated with a decreased risk of urinary incontinence and pelvic prolapse, but an increased risk of miscarriage or placenta previa in future pregnancies. Those are just some of the conclusions on a large literature review on the long-term risks and benefits associated with caesarean delivery, by Sarah Stock from the MRC Centre for Reproductive Health at the University of Edinburgh, UK, and colleagues, published this week in PLOS Medicine.

Caesarean delivery rates are rising worldwide, especially for caesareans performed without medical indication. The short-term risks and benefits of caesarean delivery have been well described. In the new study, researchers performed a systemic literature review to identify one randomized controlled trial and 79 cohort studies (29,928,274 participants total) that assessed long-term outcomes following caesarean delivery compared with vaginal delivery.

Compared with vaginal deliveries, caesarean deliveries were found to be associated with a decreased risk of urinary incontinence (1,024/7,306 cesarean delivery versus 7,713/51,594 vaginal delivery; OR 0.56 95% CI 0.47 to 0.66) and pelvic prolapse (116/4,898 cesarean delivery versus 2,055/34,310 vaginal delivery; OR 0.29 95% CI 0.17 to 0.51). Children delivered by caesarean sections had an increased risk of asthma for up to 12 years (4,788/124,668 cesarean delivery versus 23,308/763,292 vaginal delivery; OR 1.21 95% CI 1.11 to 1.32) and obesity up to 5 years of age (834/6,645 cesarean delivery versus 5,295/57,468 vaginal delivery; OR 1.59 95% CI 1.33 to 1.90). Pregnancy after caesarean delivery was associated with an increased risk of miscarriage (2,060/19,106 previous cesarean delivery versus 12,663/132,306 previous vaginal delivery; OR 1.17 95% CI 1.03 to 1.32), stillbirth (496/118,192 previous cesarean delivery versus 1,905/585,370 previous vaginal delivery; OR 1.27 95% CI 1.15 to 1.40), placenta previa (5,039/1,025,692 previous cesarean delivery versus 16,679/6,076,000 previous vaginal delivery; OR 1.74 95% CI 1.62 to 1.87), placenta accreta (44/66,241 previous cesarean delivery versus 188/638,867 previous vaginal delivery), and placental abruption (6,047/858,208 previous cesarean delivery versus 23,855/4,808,952 previous vaginal delivery; OR 1.38 95% CI 1.27 to 1.49).

Given that the findings were predominantly based on observational data, causation cannot be inferred and the findings should be interpreted with caution. Furthermore, the authors were not able to analyze the data by planned (elective) or emergency cesarean.

"This information should help inform discussions about mode of delivery, and may facilitate appropriate personalized delivery planning and shared decision making," the researchers say.

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No direct funding was obtained for the study. SJS and JEN are supported by Tommy's (registered charity no 1060508 and SCO39280). Tommy's had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The work was carried out at the MRC Centre for Reproductive Health at the University of Edinburgh.

The authors have declared that no competing interests exist.

Keag OE, Norman JE, Stock SJ (2018) Long-term risks and benefits associated with cesarean delivery for mother, baby, and subsequent pregnancies: Systematic review and meta-analysis. PLoS Med 15(1): e1002494. https://doi.org/10.1371/journal.pmed.1002494

NHS Lothian Department of Obstetrics and Gynaecology, Simpson's Centre for Reproductive Health, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom

Tommy's Centre for Maternal and Fetal Health, MRC Centre for Reproductive Health, University of Edinburgh Queen's Medical Research Institute, Edinburgh, United Kingdom School of Women's and Infants' Health, University of Western Australia, Crawley, Australia

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