Assessing survey measures of infant birth weight and birth size in Ecuador

The purpose of this study was to assess the utility of using maternal asses sments of infant birth size as proxy measures for birth weight in Ecuador, a country in which a sizeable proportion of births take place at home, wher e birth weight is typically not recorded. Four thousand and seventy-eight w omen who experienced a live singleton birth between January 1992 and August 1994 were interviewed in the Ecuador Demographic and Maternal-Child Health Survey. All women were asked if their child was weighed at birth, his/her weight, and what they considered to be his/her birth size relative to other newborns. The consistency between birth size and birth weight measures was assessed, and the differences between infants with and without reported bi rth weights were explored. The authors conclude that maternal assessments o f birth size are poor proxy indicators of birth weight. Estimates of low bi rth weight based on maternal assessments of birth size as very small should be recognized as underestimates of the actual prevalence of low birth weig ht. Moreover, infants for whom birth weights are missing should not be cons idered similar to those for whom weight was reported. Those without reporte d birth weights are more likely to be low birth weight. Thus, relying solel y on reports of numeric birth weight will underestimate the prevalence of l ow birth weight.