Endoscopy during pregnancy is associated with slight increases in risk of preterm birth and small for gestational age, but not congenital malformation or stillbirth, researchers report in a nationwide population-based cohort study published in the February issue of Gastroenterology. However, the authors believe the small increase in risk to be due to inherited factors or mother’s disease activity.
Each year in the United States, an estimated 19,000 women undergo endoscopy during pregnancy. However, studies reporting pregnancy outcomes after endoscopy have included only about 400 women. Guidelines have therefore generally discouraged endoscopy during pregnancy and, if absolutely necessary, recommend that procedures occur during the second trimester.
However, the reluctance to perform endoscopy during pregnancy might actually be harmful, if it causes a delay in diagnosis or treatment of a disorder that places the well-being of the mother or fetus at risk.
Jonas F. Ludvigsson et al collected data from the Swedish Medical Birth Register, examining the outcomes of 3052 pregnant women who underwent endoscopy (esophagogastroduodenoscopy, colonoscopy, sigmoidoscopy, or endoscopic cholangiopancreatographies) compared with 1,589,173 women who did not undergo endoscopy while pregnant. To consider the effects of disease activity, the authors examined pregnancy outcomes (preterm birth, stillbirth, small for gestational age, or congenital malformations) in women who underwent endoscopy just before or after pregnancy.
Compared with women who did not undergo endoscopy during pregnancy, women who underwent endoscopy during pregnancy had a 54% increase in risk for preterm birth and a 30% increase in risk of small for gestational age. These associations did not seem to differ with trimester of pregnancy.
In their analysis of outcomes, the authors found the mean gestational age of infants whose mothers underwent endoscopy during pregnancy to be 39.5 weeks, vs 39.9 weeks for infants born to women with no endoscopy during pregnancy. Mean birth weights were 3562 g and 3479 g, respectively, for these groups. Preterm births occurred in 4.8% of women who did not undergo endoscopy during pregnancy, and 7.6% of women undergoing any endoscopy during pregnancy.
The authors attribute the increase in risk of preterm birth and small for gestational age to disease activity in the mother, rather than the endoscopy procedure. This was because women who underwent endoscopy while they were not pregnant also had an increased risk of adverse pregnancy outcomes. Celiac disease and inflammatory bowel diseases have been associated with adverse outcomes of pregnancy. Preconception care can reduce the relapse of inflammatory bowel disease during pregnancy, and there is a low risk of birth defects for infants whose mothers are treated with tumor necrosis factor antagonists during pregnancy.
Importantly, Ludvigsson et al found no association of endoscopy with risk of either congenital malformations or stillbirths.
Ludvigsson et al state that the strength of their study is the high statistical power and its inclusion of general population and sibling controls. Other strengths include adjustment for potential confounders and the control for intra-familial factors.
However, these findings are a challenge to interpret due to limited information on duration of the endoscopy, the type of sedation and bowel preparation used, the position of the patient at endoscopy, and the indications for endoscopy.
Nonetheless, this study, the largest of its kind, should provide substantial reassurance that endoscopy is rarely associated with adverse fetal outcomes.
In an editorial that accompanies the article, Mitchell S. Cappell explains that many women have disorders that require them to undergo endoscopic examination during pregnancy, such as abdominal pain, upper gastrointestinal bleeding, dysphagia, and abnormal radiographic findings. Rare reasons for undergoing endoscopy during pregnancy include heartburn, suspected gastroesophageal reflux, dyspepsia, or nausea and vomiting. Cappell says that given that there are 18.4 million patients who undergo endoscopy each year in the United States, about 184,000 pregnant women (18,400,000 endoscopies x a 1% annual incidence of pregnancy in population) would have standard indications for gastrointestinal endoscopy.
Cappell says it is important to break the cycle of avoidance of endoscopy by generating more data and performing better studies to provide evidence-based guidelines, which should result in more endoscopies performed during pregnancy to produce more patient data for analysis.
Adequately powered studies, like that of Ludvigsson et al, provide important information for evidence-based guidelines on endoscopy during pregnancy.