Dietary therapy presents a cheap and safe way of managing Crohn’s disease, but has the disadvantage that patients need to avoid certain irritant foods if they are to prevent the disease recurring. There was therefore some concern that this could lead to dietary deficiencies during pregnancy, despite the fact that patients’ diets are checked routinely to ensure that they are indeed nutritionally adequate. We have therefore recently reviewed the progress of patients with Crohn’s disease treated by diet at Addenbrooke’s hospital who became pregnant to see what effect the diet had on the pregnancy and the pregnancy on the diet.
A retrospective survey was performed over a period over 5 years. During that time 47 pregnancies occurred in 34 women. During pregnancy Crohn’s disease remained stable or improved in 78% of patients. Delivery was by Caesarian-section in 25% and the incidence of miscarriage (21%) stillbirths (2%), congenital abnormality (0), prematurity (10%) and low birth weight (5%) were no different from those expected in the general British population. Dietary treatment in pregnancy therefore appears to be safe.
An interesting discovery was that food intolerances improved in pregnancy in 66% of these patients and many were able to eat a full diet without any flare ups during this time. After delivery however, no less than 55% relapsed within 3 months of the baby’s birth. This, we have suggested, is due to immunological changes during pregnancy. Crohn’s disease is mediated by an aggressive immune attack on the bacteria living in the bowel of a type which is labelled by immunologists as Th1. This is known during pregnancy , to change to a much milder Th2 pattern, presumably to reduce the chances of any immune attack on the developing baby, which is of course genetically different from its mother. Whilst the immune system is switched off in this way, food intolerances would improve but after the birth of the baby, the immune system reverts to its normal function, food intolerances recur and in women who are not ready for this change, a flare up of Crohn’s may occur. Its thus very important that women who are pregnant know to return to their original diet as soon as the baby has been delivered.
Crohn’s disease has been associated in the past with a number of difficulties in pregnancy including reduced fertility and increased rate of miscarriage and premature delivery and lower birth weight babies. It is very encouraging that these difficulties appear to be avoided in patients when their Crohn’s is managed by diet. Ref: Woolner J and Hunter J O, e-SPEN Journal (2014), http://dx.doi.org/10.1016/j.clnme.2014.07.001
This article was first published on the original crohns.org.uk blog. Research has moved on since, so please check current advice with your IBD team.