Caesarean delivery may increase risk of asthma, obesity in children and miscarriage in future pregnancy
Women who undergo caesarean delivery are more likely to have a lower rate of urinary incontinence and pelvic organ prolapse compared with those who undergo vaginal delivery, according to the results of a systematic review and meta-analysis. However, this finding should be weighed against the association with increased risks of fertility, future pregnancy and long-term childhood outcomes.
“We have synthesized the evidence for the long-term risks and benefits of caesarean section,” researchers said. “This information should help inform discussions about mode of delivery and may facilitate appropriate personalized delivery planning and shared decision-making.”
A total of 80 studies (one randomized controlled trial [RCT] and 79 cohort studies) were included, which involved 29,928,274 participants. Caesarean vs vaginal delivery correlated with reduced risk of urinary incontinence (n=58,900; eight studies; odds ratio [OR], 0.56; 95 percent CI, 0.47–0.66) and pelvic organ prolapse (n=39,208; two studies; OR, 0.29; 0.17–0.51). [PLoS Med 2018;15:e1002494]
Children delivered via caesarean delivery were shown to have a heightened risk of asthma up to age 12 years (n=887,960; 13 studies; OR, 1.21; 1.11–1.32) and obesity up to age 5 years (n=64,113; six studies; OR, 1.59; 1.33–1.90).
There was an association between pregnancy after caesarean delivery and increased risk of miscarriage (n=151,412; four studies; OR, 1.17; 1.03–1.32) and stillbirth (n=703,562; eight studies; OR, 1.27; 1.15–1.40), but not perinatal mortality (n=91,429; two studies; OR, 1.11; 0.89–1.39). Additionally, pregnancy after caesarean delivery correlated with elevated risk of placenta previa (n=7,101,692; 10 studies; OR, 1.74; 1.62–1.87), placenta accrete (n=705,108; three studies; OR, 2.95; 1.32–6.60) and placental abruption (n=5,667,160; six studies; OR, 1.38; 1.27–1.49).
“Although previous systematic reviews have assessed individual outcomes, we have found no other published reviews synthesizing the evidence for all long-term risks and benefits of caesarean delivery relating to mother, baby and subsequent pregnancies,” researchers said. [BIRTH 2007;34:228-237; Clin Exp Allergy 2008;38:629-633; Clin Exp Allergy 2008;38:634-642; PLoS ONE 2014;9:e87896; Int J Obes (Lond) 2013;37:893-899]
Documented evidence about medium- to long-term outcomes in women and their babies after a planned caesarean delivery or a planned vaginal birth are lacking, so the findings of this review add value to discussions regarding mode of delivery and consenting for planned caesarean delivery, they noted. [https://www.nice.org.uk/guidance/CG132]
Researchers systematically searched databases (Medline, Embase, Cochrane and Cinahl) for published studies in human participants until 25 May 2017, supplemented by manual searches. Included in the analysis were RCTs and large prospective cohort studies with ≥1-year follow-up comparing outcomes of women delivering by caesarean section and by vaginal birth.
A total of 30,327 abstracts were screened, and two assessors graded the studies for risk of bias using the Scottish Intercollegiate Guideline Network Methodology Checklist and the Risk of Bias Assessment toll for Nonrandomized Studies. Results were pooled in fixed effects meta-analyses or in random effects models when significant heterogeneity was present.
“Further research into the long-term risks and benefits of caesarean delivery on maternal request will be beneficial,” researchers said. “Whilst randomized trials might be the gold standard in this regard, one that addressed all relevant outcomes would have to be so large and with such a long follow-up so as to be likely to be unfeasible.”