Functional constipation in pregnancy and its association with dietary intake and physical activity: a cross-sectional study

Background Functional constipation (FC) is a common complaint during pregnancy and has been reported to be associated with physical activity and dietary intake. However, previous studies have reported inconsistent findings. Therefore, this study aimed to determine the prevalence of FC and examine its association with physical activity and dietary intake among pregnant women.Method In this cross-sectional study, 381 healthy pregnant women attending urban health centres in Tabriz, Iran, between January 2024 and February 2025, were selected using a multistage cluster sampling method. FC was diagnosed according to the Rome IV criteria. Data were collected through face-to-face interviews using the International Physical Activity Questionnaire (IPAQ) and the Food Frequency Questionnaire (FFQ). Multivariable Generalised Estimating Equations (GEE) analysis was performed to identify factors associated with FC.Results The overall prevalence of FC throughout pregnancy was 37%. In the first trimester, 41 out of 73 women (56%) had FC, while in the second trimester 53 out of 146 women (36%), and in the third trimester 47 out of 162 women (29%) were affected. Multivariate GEE indicated that both higher dietary fibre intake (aOR= 0.88, 95%CI 0.86-0.91, p p p = 0.009), whereas, secondary education was associated with a higher risk (aOR= 2.81, 95%CI 1.33-5.95, p = 0.007). Physical activity (aOR= 1.00; 95%CI 1.00 to 1.01; p = 0.168), and other demographic characteristics (p > 0.05) were not independently associated with FC after adjustment.Conclusion FC is highly prevalent during pregnancy and may adversely affect women's quality of life. Higher dietary fibre and fluid intake were associated with lower odds of FC, highlighting the importance of healthy lifestyle behaviours during pregnancy. Prospective longitudinal studies are warranted to confirm these findings.