Gluten-free diet during pregnancy and pregnancy outcome: A retrospective cohort study

Objective: A gluten-free diet (GFD) is becoming increasingly popular, especially among young females, and including those without diagnosed celiac disease (CD). Whether a GFD is appropriate during pregnancy remains unclear. Our primary aim was to evaluate the association of a GFD and neonatal birthweight and incidence of large for gestational age (LGA) and small for gestational age (SGA). Secondarily, we sought associations with other obstetric outcomes. Methods: The data was collected retrospectively from the Tampere University Hospital database. The study period was from January 2015 to April 2021. The diet information was obtained from self-reported questionnaires. All women following a GFD were included. A total of 79 had CD and 291 followed a GFD without CD diagnosis. The latter are referred to here as people without CD avoiding gluten (PWAG). A total of 456 omnivores were randomly chosen to constitute a control group. Outcomes were analyzed by comparing gluten-free groups to a control group. Results: The median birth weight was higher in the GFD group compared to the controls (3533 vs. 3440 g, P < 0.003), but the incidences of SGA or LGA did not differ between the study groups. The incidence of pregnancy complications was comparable between the groups. Induction of labor was more frequent (aOR 1.52; 95% CI: 1.12-2.08), and the duration of labor was longer (aOR1.56; 95% CI: 1.18-2.06) in the GFD group, especially among PWAG. However, no difference in the cesarean section rate were found between the groups. Conclusion: In the present retrospective cohort study, a GFD did not appear to be associated with adverse pregnancy or neonatal outcomes.