Does Pregnancy Increase Risk of Ventral Hernia Recurrence?

The investigators will establish a cohort of female fertile patients who underwent ventral hernia repair (Umbilical, Epigastric and Incisional hernia repair) registered in the Danish Hernia Database. The investigators will link these data at an individual level with the Danish National Patient Registry (DNPR), Danish Medical Birth Registry (DMBR) and the Danish Civil Registry (CPR). From DMBR, subsequent pregnancies in the study cohort will be noted. From DNPR, ventral hernia recurrence, defined as clinical recurrence and/or reoperation for recurrence will be noted. Cases registered with both clinical recurrence and reoperation for recurrence, the date of the earliest registration will be defined as the date of ventral hernia recurrence. From CPR, date of death or emigration will be noted. Through an extended Cox regression analysis, handling pregnancy as a time-dependent variable, the investigators will examine whether pregnancy is associated with an increased risk of ventral hernia recurrence.