Prenatal biopsychosocial risk assessment and low birthweight.

A double-blind prospective study was conducted to compare the predictive value of a prenatal biomedical risk scale (PBRS) and a prenatal biopsychosocial risk assessment (PBRAS) with respect to low birthweight. All obstetric patients at seven health centers located in Argentina, Colombia, Honduras, and Uruguay from November 1992 through January 1994 whose initial prenatal visits occurred between the 14th and 28th week of gestation were invited to participate. Information was obtained on 979 mother-infant pairs. High PBRS scores showed sensitivity of 62.1% and specificity of 81.3%, positive predictive value (PPV) of 45.3% and negative predictive value (NPV) of 89.5%, with respect to low birthweight. With the addition of the psychosocial factors (PBRAS), sensitivity of 75.7% and specificity of 76.1%, PPV of 55.1% and NPV of 88.9% were observed. The prospective cohort design of this study provides a strong basis for conclusion that an evaluation of the prenatal biopsychosocial risk (as operationalized by the PBRAS) adjusted for other variables such as length of gestation, neonatal APGAR, perinatal mortality, socioeconomic status, drinking and smoking improves the positive predictive value of the assessment of women who may give birth to newborns with low birthweight (P < 0.01).