Endoscopy is an integral part of the investigation and management of gastrointestinal disease. 

Dr Jonas Ludvigsson and colleagues from Sweden examined outcomes of pregnancies for women who underwent endoscopy during their pregnancy.

The researchers performed a nationwide population-based cohort study, linking data from the Swedish Medical Birth Registry with those from the Swedish Patient Registry. 

The research team identified 3052 pregnancies exposed to endoscopy. 

The team calculated adjusted relative risks for adverse outcomes of pregnancy according to endoscopy status using 1,589,173 unexposed pregnancies as reference. 

To consider the effects of disease activity, the researchers examined pregnancy outcomes in women who underwent endoscopy just before or after pregnancy. 

The team's secondary outcome measures included induction of labor, low birth weight, cesarean section, Apgar score <7 at 5 minutes, and neonatal death within 28 days. 

To consider intrafamilial factors, the researchers compared pregnancies within the same mother.

Exposure to any endoscopy during pregnancy was associated with an increased risk of preterm birth or small for gestational age but not of congenital malformation or stillbirth. 

The research team found that none of the 15 stillbirths to women with endoscopy occurred <2 weeks after endoscopy. 

The team observed that adjusted relative risks were independent of trimester. 

Compared to women with endoscopy <1 year before or after pregnancy, endoscopy during pregnancy was associated with preterm birth but not with small for gestational age, stillbirth, or congenital malformation. 

The research team noted that restricting the study population to women having an endoscopy during pregnancy or before/after, and only analyzing data from women without a diagnosis of inflammatory bowel disease, celiac disease, or liver disease, endoscopy during pregnancy was not linked to preterm birth. 

Comparing births within the same mother, for which only 1 birth had been exposed to endoscopy, the team found no association between endoscopy and gestational age or birth weight.

Dr Ludvigsson's team concludes, "In a nationwide population-based cohort study, we found endoscopy during pregnancy to be associated with increased risk of preterm birth or small for gestational age, but not of congenital malformation or stillbirth."

"However, these risks are small and likely due to intrafamilial factors or disease activity."