Maternal weight gain and intestinal permeability marker zonulin in late pregnancy: implications for nutritional and metabolic health

BACKGROUND: Gestational weight gain (GWG) outside recommended ranges has been associated with adverse maternal and neonatal outcomes; however, the underlying biological mechanisms remain incompletely understood. Intestinal permeability, assessed using serum zonulin, has emerged as a potential pathway linking metabolic and inflammatory changes during pregnancy. METHODS: This cross-sectional study included 51 pregnant women with normal pre-pregnancy body mass index and their neonates. Participants were classified according to gestational weight gain as within or above recommended limits. Maternal serum samples collected at 30–35 weeks of gestation and cord blood samples obtained at delivery were analyzed for zonulin and total oxidant status. Associations were examined using both categorical and continuous measures of gestational weight gain. RESULTS: Higher gestational weight gain was associated with increased maternal and fetal serum zonulin concentrations. Maternal and fetal zonulin levels were positively correlated with each other, and maternal zonulin showed a modest inverse association with neonatal birth weight. Analyses treating gestational weight gain as a continuous variable yielded consistent findings. Given the sample size, results should be interpreted cautiously. CONCLUSIONS: This exploratory study suggests that higher gestational weight gain is associated with increased maternal and fetal serum zonulin concentrations among women with normal pre-pregnancy body mass index. Given the cross-sectional design and modest sample size, causal inferences cannot be drawn. The findings should be considered hypothesis-generating and warrant confirmation in larger, longitudinal studies incorporating comprehensive metabolic and inflammatory assessments.