Crohn’s disease (CD), a form of Inflammatory Bowel Disease (IBD), is a chronic condition characterized by inflammation that can affect any part of the digestive tract. Since CD often presents during a woman’s reproductive years, concerns arise about its impact on pregnancy. The vast majority of women with the condition successfully carry their pregnancies to term, resulting in healthy outcomes. Effective management requires proactive planning and continuous collaboration between a gastroenterologist and an obstetrician, often beginning before conception. The greatest influence on a positive maternal and fetal prognosis is the control of disease activity.
Conception and Fertility
Women often worry if Crohn’s disease will prevent them from becoming pregnant. For women whose disease is in remission, the ability to conceive is generally comparable to that of the general population. Active inflammation, however, can temporarily reduce fertility rates due to systemic illness, poor nutrition, or inflammation affecting the ovaries or fallopian tubes.
Surgical history, particularly involving the pelvis, can be a more significant factor in fertility reduction than the disease itself. Procedures like ileal pouch-anal anastomosis (IPAA) can lead to pelvic scar tissue and adhesions. These adhesions may impair the function of the fallopian tubes, decreasing the chances of natural conception. Women who have undergone open IPAA may experience more compromised fecundity rates compared to those who had a laparoscopic procedure.
Impact of Disease Activity on Pregnancy Outcomes
Disease activity at conception is the single most important predictor of maternal and fetal outcomes. Women who conceive while in remission have outcomes similar to those without IBD, and their risk of a flare during pregnancy is low. It is strongly recommended that women delay conception until they have achieved remission for at least three to six months.
Active Crohn’s disease during gestation significantly increases the chance of adverse pregnancy events. Active inflammation raises the risk of preterm birth, low birth weight, and spontaneous abortion. Furthermore, active disease interferes with the mother’s ability to absorb nutrients, which can restrict fetal growth.
Approximately one-third of women in remission at conception will experience a flare during pregnancy, while two-thirds of those with active disease will see their condition worsen. The inflammatory environment created by a flare contributes to poor placental function and nutrient delivery. Continuous monitoring is necessary, as pregnancy itself does not guarantee continued remission.
Medication Safety and Management During Pregnancy
Many women worry about continuing necessary medication while pregnant. Stopping effective Crohn’s medication is often more hazardous than continuing it, as the risk of active disease outweighs the theoretical risks of most treatments. Since the goal is to maintain remission, most medications used to control Crohn’s disease can be safely continued throughout pregnancy and lactation.
Aminosalicylates (e.g., mesalamine and sulfasalazine) are safe during all stages of pregnancy. Women taking sulfasalazine should increase folic acid supplementation to 2 milligrams daily to counteract its effect on folate absorption. Immunomodulators, such as thiopurines (azathioprine and mercaptopurine), are often safely continued for maintenance of remission, though they are typically not started during pregnancy due to their slow onset of action. Thiopurines do not significantly increase the risk of congenital abnormalities.
Biologic therapies, particularly anti-tumor necrosis factor (anti-TNF) agents like infliximab and adalimumab, have been extensively studied and are considered safe. These large antibody molecules cross the placenta, especially during the latter half of pregnancy. To minimize fetal exposure, some anti-TNF agents may be tapered or discontinued in the third trimester, though this decision must balance the risk of a flare. Certolizumab pegol limits placental transfer and may not require dose adjustments later in pregnancy.
Newer biologics, such as vedolizumab and ustekinumab, also appear safe for use during pregnancy. While they demonstrate placental transfer, studies have not found safety signals related to growth or psychomotor development in exposed children. Methotrexate must be discontinued well before conception, ideally at least three months prior, due to its association with birth defects.
Delivery, Postpartum Care, and Breastfeeding
The mode of delivery depends on the patient’s Crohn’s disease status, particularly perianal involvement. For women with quiescent disease and no history of perianal fistulas or abscesses, a vaginal delivery is safe and preferred. A Cesarean section is typically reserved for standard obstetric indications, similar to the general population.
If a woman has active perianal disease, such as draining fistulas or abscesses near the rectum, a Cesarean section is usually recommended. This is because the trauma and potential tearing of the perineum during a vaginal delivery can significantly worsen active perianal disease and increase the risk of infection.
The postpartum period carries a substantial risk of disease flare. Approximately 30% of women experience a flare within the first year after delivery. Active disease during the third trimester and stopping medication after delivery are strong predictors of a postpartum flare. Maintaining medication adherence and continuous monitoring by the gastroenterologist is paramount following birth.
Most Crohn’s medications, including aminosalicylates, thiopurines, and many biologics, are compatible with breastfeeding. The amount of drug that passes into breast milk is often negligible, and the benefits of breastfeeding generally outweigh the minimal risk of infant exposure. Women should confirm the safety of their specific regimen with their medical team.
Hereditary Risk of Crohn’s Disease
Parents often worry about passing Crohn’s disease to their child, as the condition has a genetic component. Crohn’s disease is a complex, multifactorial illness that results from a combination of genetic predisposition and environmental factors. Having a first-degree relative, such as a parent, with CD does increase the risk compared to the general population.
The lifetime risk for a child to develop Crohn’s disease when one parent has the condition is typically cited in the range of 7% to 9%. While this risk is notably higher than the background rate in the general population, the vast majority of children born to parents with CD will not develop the condition. If both parents have some form of IBD, the child’s risk increases to about 35%.