Macrosomic Infants Born to Non-diabetic Mothers in Nova Scotia: Determinants and Development of a Risk Prediction Model

Abstract

This retrospective cohort study investigated the rates and risk factors of macrosomia in non-diabetic women and developed a clinically relevant model to predict macrosomia in mid-pregnancy. Logistic regression was used to identify risk factors of macrosomia. Risk scoring systems were developed for nulliparous and multiparous women separately using linked Atlee Perinatal Database and IWK lab data from glucose challenge tests (GCT). The scoring systems were validated by the c-statistic. Of the infants, 15.3% were macrosomic. In nulliparous women, the largest number of points was assigned for pre-pregnancy weight >90 kg, (OR: 4.8; 95% CI: 3.9-6.0). Other factors contributing points were increasing rate of weight gain and GCT results, male sex, married or common-law and absence of a psychiatric illness, smoking and asthma. The resulting risk score corresponded to a range of estimated risk of 0.2% to 47.0%, depending on the factors present. The c statistic for the model was 0.70.