Maternal risk factors for potential maltreatment deaths among healthy singleton and twin infants

Our aim was to evaluate the risk of death among healthy infants due to maltreatment, using national linked vital statistics data. The study population included all nonanomalous, full-term (> or = 37 weeks), non-low birthweight (> 2500 grams) infants born between 1995 and 2000 and their linked death certificates: 18,673,439 singleton pregnancies (36,864 deaths) and 77,800 twin pregnancies (356 pregnancies with a death). The underlying cause of death was characterized as due to maltreatment, sudden infant death syndrome (SIDS), and other causes, based on ICD-9 and ICD-10 codes, and modeled by maternal age using multinomial logistic regression; mothers aged 25 to 29 were the reference group. The highest risk for infant mortality was among the youngest mothers for maltreatment (AOR 2.45 and 1.95 for singleton mothers < 20 and aged 20 to 24, respectively; AOR 4.34 and 2.25 for twin mothers < 20 and aged 20 to 24, respectively). The risk of death overall and for each category was modeled by maternal age < 20, aged 20 to 24, and > or = 25, with and without the father's age present on the birth certificate, with mothers > or = 25 and father's age present as the reference group. All risks of death were significantly increased for mothers younger than age 25, with the highest risks among the youngest mothers and missing father's age. The pattern for twins was similar, with elevated risks among younger mothers with or without father's age present on the birth certificate. These results add to the body of knowledge regarding risk factors for infant mortality among healthy singletons and twins.