How family history plays a part in IBD

Heredity and IBD

The heredity implications of pregnancy with IBD

If you or a relative has Crohn's disease or ulcerative colitis, you might wonder what role family history plays in IBD, especially when it comes to having children of your own. We're here to help you understand how IBD can be passed down through families, so you can be informed as you prepare for the road ahead.

Of course, talking with a doctor who specializes in the treatment of IBD in pregnancy is the best way to understand your specific situation, but you can get more IBD information by exploring the questions and answers below.

How often is there a family history of IBD?

Having an affected family member with IBD is the strongest risk factor for developing the disease. Overall, around 12% of patients with Crohn's disease and 9% of patients with ulcerative colitis report a positive family history.

What is the risk of developing IBD for a child with a family history of the disease in comparison to the general population?

For children born to families with a history of IBD, the risk for developing the disease is increased relative to the general population. Think of it this way: out of 10,000 people who make up the "general population" about two individuals per year have a chance of developing IBD. If you factor in family history, the number of people at risk of developing IBD increases by 4 to 8 times that of the general population. It's important to keep in mind that the real risk (what doctors call absolute risk) is still very small – lower than 5%. In some instances, certain ethnic groups, like the Ashkenazi Jewish population, have a slightly higher risk.

Does the risk increase or decrease depending on which family member is affected?

Yes. The risk of IBD depends on the exact relationship to the family member affected with the disease. Risk is higher if there are first-degree relatives affected, as compared to second-degree relatives. The highest risk is observed when both the mother and the father have IBD. In this rare situation, around 1/3 of the descendants will develop IBD.

What if multiple family members are affected with IBD?

When there are more than two family members affected, especially if these are first-degree relatives, the risk of inheriting IBD for the offspring increases. The families at greatest risk are those who have three or more first-degree relatives affected.

Can I do anything to prevent transmitting IBD to my child?

Research is continuing to evolve in this area, but the reasons why IBD runs in families are not fully understood since genetics only explains a small fraction of how the disease is inherited. It is possible that other shared risk factors, like environment and/or the microbiome (the bacteria living inside one's gut), also play a role.

It's natural for parents to try to shield their children from anything that could potentially cause them pain. When it comes to IBD, there are no known steps you can take to decrease the risk of passing IBD on to your child. But, you can continue to learn about IBD and help your child manage the disease, should he or she inherit it. After all, you can pass down knowledge to your child, as well.

Try not to worry

While it's easy to fear passing IBD to your little one, it's important to focus on the things you do have control over during your pregnancy, rather than those you cannot. Talk to your doctor about ways you can help reduce your child's risk of inheriting IBD and the steps you can take to ensure a healthy pregnancy and delivery.