Are clinical criteria just proxies for socioeconomic status? A study of low birth weight in Jamaica.

Objective: To determine if the clinical risk factors for low birth weight are independent of socioeconomic risk factors in a population based sample from a developing country.
Design: Survey data from patient reported socioeconomic measures and their most recent pregnancy history.
Setting: A national sample of randomly selected households in Jamaica.
Subjects: All women aged 14-50 in the household who had a pregnancy lasting seven months in the past five years (n = 952).
Main Outcome Measure: Birth weight.
Results: Clinical risk factors for low birth weight, such as parity age, are independent of socioeconomic determinants, such as consumption and where a mother lives. Women who are nulliparous, 35 or older, poor, or living in certain areas are more likely to have lower birth weight children than those that do not have these characteristics (t statistics > 2.0). The addition of socioeconomic factors to the multiple regression does not alter the estimates for the clinical risk factors for low birth weight. Thus, the effect of being nulliparous can be offset by being in the highest consumption quintile and, conversely, the risk of being older will be compounded if women are poor.
Conclusions: Both clinical and socioeconomic risk factors should be used to target women at risk. In terms of the quality of care, this study links clinical and socioeconomic risk factors to poor outcomes. Further studies are needed, however, to link the quality of care at various locations to these outcomes.