Incisional hernia repair after caesarean section: a population based study

Abstract

BACKGROUND Incisional hernias occur at surgical abdominal incision sites but the association with caesarean section (CS) has not been examined. AIM: To determine whether CS is a risk factor for incisional hernia repair. MATERIAL and METHODS: Population-based cohort study in Australia using linked birth and hospital data for women who gave birth from 2000 to 2011. (n=642,578) Survival analysis was used to explore the association between CS and subsequent incisional hernia repair. Analyses were adjusted for confounding factors including other abdominal surgery. The main outcome measure was surgical repair of an incisional hernia. RESULTS: 217,555 women (33.9%) had at least one CS and 1,554 (0.2%) had an incisional hernia repair. The frequency of incisional hernia repair in women who had ever had a caesarean section was 0.47%, compared to 0.12% in women who never had a caesarean section. After controlling for different follow up lengths and known explanatory variables, the adjusted hazard ratio (aHR) was 2.73 (95%CI 2.45-3.06, P <0.001). Incisional hernia repair risk increased with number of caesarean sections: women with two CS had a threefold increased risk of incisional hernia repair, which increased to 6 fold after five CS (aHR=6.29, 95%CI 3.99-9.93, P<0.001) compared to women with no CS. Prior abdominal surgery including other hernia repair also increased the risk of incisional hernia repair (all p<0.001). CONCLUSIONS: There was a strong association between maternal CS and subsequent incisional hernia repair, which increased as the number of CSs increased, but the absolute risk of incisional hernia repair was low.