MATERNAL INFLUENCES ON CORD-BLOOD LEAD LEVELS

We constructed models of umbilical cord blood lead (PbB), with and wit hout the addition of maternal PbB as delivery and earlier in pregnancy , to determine which factors explaining cord PbB depended upon materna l PbB and which did not.We prospectively studied women of low-to-middl e socioeconomic status who lived in the Valley of Mexico from 12 weeks of pregnancy to delivery. We measured maternal venous PbB during preg nancy and at delivery, and umbilical cord PbB (1-38 mu g/dl, 0.05-1.83 mu mol/l). We used multiple regression analyses to model cord PbB and a legit analysis to model the maternal-cord PbB relationship Older mo thers using lead-glazed pottery and canned foods delivered babies with increased cord PbB, while those with occasional alcohol use during pr egnancy, high milk intake, and more spontaneous abortions delivered ba bies with lower cord PbB. Maternal PbB at 36 weeks of pregnancy and at delivery independently explained additional variance in cord PbB, but maternal PbB earlier in pregnancy did not. Some of the effects of lea d-glazed pottery, maternal abortions, alcohol use, and canned food use on cord PbB were mediated through maternal PbB. The effects of matern al age and milk intake on cord PbB were independent of their influence on maternal PbB near delivery. Cord PbBs were higher than maternal Pb Bs at delivery in 33% of the cases, and were predominant in mothers ov er 30 and those drinking milk less than once per day. Measurable influ ence of maternal PbB on delivery cord PbB is limited to the four to ei ght weeks prior to delivery. Many factors suspected of influencing bon e lead also control cord PbB, some of them independently of their effe ct on maternal delivery PbB. Minimizing fetal exposure near the end of pregnancy may require long-term control of maternal lead exposure and good management of pregnancy and diet.