Objective: To identify social, behavioral, and physiological risk factors associated with small for gestational age (SGA) by gestational age category in St. Louis City and County.
Methods: A retrospective cohort study was conducted using birth certificate and fetal death records from 2000 to 2009 (n = 142,017). Adjusted associations of risk factors with SGA were explored using bivariate logistic regression. Four separate multivariable logistic regression analyses, stratified by gestational age, were conducted to estimate adjusted odds ratios.
Results: Preeclampsia and inadequate weight gain contributed significantly to increased odds for SGA across all gestational age categories. The point estimates ranged from a 3.41 increased odds among women with preeclampsia and 1.76 for women with inadequate weight gain at 24-28 weeks' gestational age to 2.19 and 2.11 for full-term infants, respectively. Among full-term infants, smoking (aOR = 2.08), chronic hypertension (aOR = 1.46), and inadequate prenatal care (aOR = 1.25) had the next most robust and significant impact on SGA.
Conclusion: Preeclampsia and inadequate weight gain are significant risk factors for SGA, regardless of gestational age. Education on the importance of nutrition and adequate weight gain during pregnancy is vital. In this community, disparities in SGA and smoking rates are important considerations for interventions designed to improve birth outcomes.