To Örebro University

Introduction: Hernia of the linea alba (ventral hernia) is a common surgical condition that affects both men and women. The association between pregnancy and risk of developing ventral hernias is unclear. This study aimed to assess the risk of developing a primary ventral hernia requiring repair, and whether increasing parity is associated with a greater risk of developing a ventral hernia.

Method: This nationwide cohort study included women born between 1950-1980 who were registered in the Swedish Medical Birth Register (MBR). Data on pregnancies and vaginal or caesarean sections were retrieved from the Birth Register. The cohort was cross-matched with the National Patient Register (NPR) to identify subsequent primary hernia repairs.

Result: This study included 1,630,754 women born between 1950 and 1980. Among these, 1,588,609 (97.4%) were registered in MBR. The incidence rates for Umbilical Hernia Repair (UHR) and Epigastric Hernia Repair (EHR) were 13.2/100,000 person-years and 5.4 per 100,000 person-years, respectively. When compared with women registered for one delivery, the incidence rate ratio for UHR was higher among those with two deliveries (1.3, 95% CI: 1.26-1.33) and among those registered with ≥3 deliveries (1.6, 95% CI: 1.58-1.68).

The incidence rate ratios were 1.29 (95% CI: 1.20-1.39) and 1.34 ( 95% CI: 1.24-1.45) for EHR among women with two and ≥3 registered deliveries, respectively.

Discussion: A history of more than one pregnancy is associated with an increased incidence of umbilical and epigastric hernias. The incidence rate of UHR and EHR was higher in women who underwent caesarean delivery than in those who underwent vaginal delivery.