A study on the correlation between pregnancy risk factors and birth outcomes

Abstract

Adverse birth outcomes-including low birth weight (LBW, < 2500 g), preterm birth (PTB, < 37 weeks), and intrauterine growth abnormalities-remain major global public health challenges, particularly in low- and middle-income countries. Although maternal body mass index (BMI) and gestational weight gain (GWG) are established risk factors in Western populations, their interactions with metabolic and sociodemographic factors in Asian cohorts, particularly within China's rapidly urbanizing populations, warrant further investigation. This prospective cohort study analyzed 1,026,294 singleton pregnancies (2012-2018) from the Liaoning Maternal and Child Health Information System. Using multivariate logistic regression models, we calculated adjusted risk ratios (RR) with 95% confidence intervals (CI) to evaluate associations between prenatal exposures… and birth outcomes: low birth weight (LBW), macrosomia (> 4000 g), Small-for-gestational-age (SGA, < 10th percentile), Large-for-gestational-age (LGA, > 90th percentile), PTB. Pre-pregnancy underweight (RR = 1.58, 95% CI 1.47-1.70), insufficient gestational weight gain (RR = 1.44, 95% CI 1.36-1.53), and preeclampsia (RR = 3.61, 95% CI 3.18-4.10) were strongly associated with low birth weight. For SGA, pre-pregnancy underweight (RR = 1.68, 95% CI 1.62-1.74) and insufficient GWG (RR = 1.40, 95% CI 1.29-1.51) were key predictors. Conversely, pre-pregnancy obesity (RR = 2.79, 95% CI 2.72-2.85) and excessive GWG (RR = 2.15, 95% CI 2.07-2.23) elevated macrosomia risk. PTB was strongly associated with pre-pregnancy obesity (RR = 1.29, 95% CI 1.25-1.33), assisted reproductive conception (RR = 3.39, 95% CI 3.01-3.83), and early-pregnancy hyperglycemia (RR = 1.19, 95% CI 1.15-2.22). Pre-pregnancy BMI, gestational weight gain (GWG), hypertensive disorders, and metabolic markers (e.g., fasting glucose, hemoglobin) constitute critical modifiable determinants of adverse birth outcomes. These findings quantify region-specific risk thresholds (e.g., 38.1% pre-pregnancy overweight/obesity vs. national 24.8%, Liaoning macrosomia 11.62% vs. national 8.9%) to prioritize GWG monitoring and metabolic screening in Northeast China's urban transition.

Keywords: Adverse birth outcomes; Gestational weight gain; Maternal BMI; Metabolic risk factors; Population-based cohort; Preterm birth.