Blood lead levels in newborn children and mothers covered by the Mexican Institute of Social Security.

Objective. To establish the relation between maternal blood lead (MBL) and umbilical cord blood lead (CBL) levels during delivery, and to determine th e major predictors for MBL in women covered by the Mexican institute of Soc ial Security (MISS), in Mexico City. Material and methods. From 1991 to 199 3, a cross-sectional study was conducted in four MISS hospitals, among norm al pregnant women who volunteered to participate. Blood samples were taken from women and from the umbilical cord during delivery. Statistical analysi s consisted of descriptive statistics and simple and multiple linear regres sion. Results. A total of I 404 mother-newborn pairs were studied. Mean mat ernal age was 25 years. MBL average was 10.7 +/- 6.5 mug/dl; no significant differences were found by hospital, age, or marital status. Mean CBL was 1 0.4 +/- 6.2 mug/dl. A log unit increase in MBL corresponded to a log increa se of 0.62 in CBL (p < 0.01). Pearson's correlation was 0.6 I (p < 0.01). T he main predictors of MBL were: Use of lead-glazed ceramic (positively asso ciated) and milk and orange juice intake (negatively associated). Forty-sev en percent of mothers and 50 percent of the newborn babies had values highe r than 10 mug/dl, and 578 of them had blood lead levels higher than their m others. Conclusions. Further studies should be carried out in order to iden tify necessary interventions.