Inflammatory bowel disease (IBD) is a lifelong chronic condition, and has a high prevalence in young adults. Many women with IBD are of reproductive age. Having IBD appears to impact women who are contemplating having children as voluntary childlessness is more common in women of child bearing age with IBD {1}. Concerns include fertility, fetal outcomes and the effect of pregnancy on the disease itself {1}.
Women who have disease remission and no previous pelvic surgery have fertility rates similar to women of a similar age without IBD. If conception occurs at a time of quiescent disease, then the risk of relapse is similar to non-pregnant women with IBD. If conception occurs when disease is active two thirds of women will have persistent activity and two thirds of these will deteriorate during pregnancy {2}. Active disease at conception or during pregnancy has been shown to increase adverse fetal outcomes such as low birth weight, preterm birth and fetal loss {3, 4}. One study of 298 pregnancies identified a 19% spontaneous abortion rate in women with IBD {5}. In one large Swedish study an increased risk of preterm birth and low birth weight was identified with IBD, and the risk of these complications was higher with active disease during pregnancy {6}. Stephansson et al found patients with ulcerative colitis with active disease had increased risks of adverse pregnancy outcomes compared to the general population {7}. Maintaining quiescent disease prior to and during pregnancy is the main determinant of good outcomes for both mother and fetus.
The early identification of flares of IBD is essential to avoid progression of disease activity and symptoms. Symptoms can however be misleading, particularly in pregnancy when gastrointestinal symptoms such as nausea, abdominal cramps and altered bowel movements are common. Non-invasive markers of inflammation such as C-reactive protein (CRP), albumin and haemoglobin can help in the diagnosis of a flare, but are not specific to gastrointestinal inflammation. Endoscopy is the gold standard for identifying and quantifying disease activity in a flare of IBD, and while it is unlikely to be harmful, safety of endoscopy in pregnancy has not been well studied and in general, both endoscopists and pregnant women prefer to avoid performing endoscopy in pregnancy. The American Society for Gastrointestinal Endoscopy guidelines state that endoscopic procedures are only justified in pregnancy when the benefit to both mother and fetus outweighs the risk {8}.
Faecal calprotectin (FCP) is a biochemical marker of inflammation that is specific to the gastrointestinal tract and its use as a non-invasive marker of IBD flares has become more widespread over the past 10 years. Calprotectin is a 36kDa calcium and zinc binding protein expressed by neutrophils. Once a neutrophil migrates to a site of chemoattraction it sets off a cascade of events eventually leading to the release of its cytosolic granules and calprotectin. The amount of calprotectin measured in a stool sample therefore reflects the number of participating neutrophils in an area of inflammation {9}. FCP is a sensitive and specific non-invasive marker of bowel inflammation and is therefore very useful as a marker of disease activity in patients with known IBD. FCP has been shown to reflect endoscopic disease activity in Crohn’s disease {10, 11} and is more sensitive than symptoms or CRP at detecting intestinal inflammation {11, 12}. In many cases, calprotectin levels begin to increase before patients develop symptoms {13}. Amongst various different biological markers, FCP has emerged as the superior non-invasive marker of gastrointestinal inflammation. FCP has become an integral component in the management of IBD and is particularly useful in pregnancy where there is a desire to avoid endoscopy. FCP levels have been studied in pregnant women with known IBD and studies have shown FCP appears to correlate with disease activity in IBD in pregnancy {14} however few data exist on the effects of pregnancy itself on calprotectin levels in patients without IBD or trends in FCP levels during pregnancy and the post-partum period. A single study by Balint et al compared FCP levels in healthy pregnant and non-pregnant women as well as pregnant and non-pregnant women with IBD and showed no effect of pregnancy on FCP, but did not examine the levels of FCP at different stages of pregnancy and the post-partum period {15}. FCP may also be affected by other factors such as body mass index (BMI) and cigarette smoking. A study of lifestyle factors and FCP as a measure of colorectal cancer risk, found that in healthy individuals there was a 40% increase in FCP levels per increase in BMI by 10 kg/m2 and an increase in FCP in cigarette smokers {16}. In order to reliably use FCP as a marker of inflammation in pregnant women with IBD, it is necessary to understand the effect of pregnancy on FCP in healthy women.
In this study we aimed to determine variations in faecal calprotectin levels during pregnancy and the post-partum period in a cohort of healthy women. We also aimed to examine the effect, if any, of BMI, cigarette smoking and parity on FCP levels in pregnant healthy women.