Paradoxical Impact of Ileal Pouch-Anal Anastomosis on Male and Female Fertility in Patients With Ulcerative Colitis.

Background: Birth rates in males with ulcerative colitis and ileal pouch-anal anastomosis have not been studied.

Objective: This study aimed to estimate birth rates in males and females with ulcerative colitis and study the impact of ileal pouch-anal anastomosis.

Design: This was a retrospective registry-based cohort study that was performed over a 30-year period.

Settings: Records for parenting a child from the same period were cross-linked with patient records, and birth rates were calculated using 15 through 49 years as age limits. All data were prospectively registered.

Patients: All patients with ulcerative colitis and ulcerative colitis with ileal pouch-anal anastomosis between 1980 and 2010 were identified in Danish national databases.

Main Outcome Measures: The primary outcomes measured were birth rates in females and males with ulcerative colitis and ulcerative colitis with ileal pouch-anal anastomosis.

Results: We included 27,379 patients with ulcerative colitis (12,812 males and 14,567 females); 1544 had ileal pouch-anal anastomosis (792 males and 752 females). Patients with ulcerative colitis have slightly reduced birth rates (males at 40.8 children/1000 years, background population 43.2, females at 46.2 children/1000 years, background population 49.1). After ileal pouch-anal anastomosis, males had increased birth rates at 47.8 children/1000 years in comparison with males with ulcerative colitis without ileal pouch-anal anastomosis (40.5 children/1000 years), whereas females had reduced birth rates at 27.6 children/1000 years in comparison with females with ulcerative colitis without ileal pouch-anal anastomosis (46.8 children/1000 years).

Limitations: Only birth rates were investigated and not fecundability. Furthermore, there is a question about misattributed paternity, but this has previously been shown to be less than 5%.

Conclusions: Ulcerative colitis per se has little impact on birth rates in both sexes, but ileal pouch-anal anastomosis surgery leads to a reduction in birth rates in females and an increase in birth rates in males. This has clinical impact when counseling patients before ileal pouch-anal anastomosis surgery.