Impact of the trait anxiety during pregnancy on birth weight: an observational cohort study

To explore the effects of antenatal anxiety on fetal growth an observational cohort study was performed, including a cohort of 204 women with singleton pregnancies during the strict lockdown of the COVID-19 pandemic in 2020. Psychosocial factors, maternal demographics, obstetric outcomes, social support (Medical Outcomes Study Social Support Survey, MOS-SSS), and symptoms of anxiety (State-Trait Anxiety Inventory, STAIs and STAIt) and depression (Edinburgh Postpartum Depression Scale, EPDS) were studied as potential predictors of low birth weight. Main outcome measures were birth weight, head circumference and length. Results showed a negative correlation between STAIt score (trait anxiety) and birth weight percentile (r = -0.228, p = .047). In the univariate linear regression analysis, a lower maternal weight and BMI before pregnancy, parity, increased STAIt score and preterm birth below 37 weeks of gestation (p = .008, p = .015, p = .028, p = .047 and p = .022, respectively) were identified as predictive risk factors for low birth weight, whereas in the multivariate lineal regression analysis only a lower maternal weight before pregnancy and an increased STAIt score were independent predictors for low birth weight (p = .020, p = .049, respectively). To conclude, anxiety during pregnancy impacts birth weight, and specifically the trait anxiety, is a predictor for low birth weight.