Abstract: Objective T o investigate the probable effects of lead exposure during pregnancy on auditory development in infants.Methods The specimens of blood were collected form women at the second three months of gestation and delivery and from umbilical cord,and Pb-B levels were determinded as a marker to reflect lead exposure.BAEP was recorded in infants at 6 months of age as effective indicators to study effects of lead on their auditory development.Results(1)The Pb-B levels were(0.289±0.050)μmol/L at the second three months of gestation,(0.242±0.049)μmol/L at delivery,(0.197±0.051)μmol/L from umbilical cord.(2)There was a significant association between the Pb-B level of umbilical cord and the latencies of waves Ⅰ、Ⅲ and Ⅴ at rightear.All the children were divided into two groups(high-blood-lead and low- blood-lead)according to the cut-off value for umbilical blood level of 0.242μmol/L,results indicated that latencies of wave Ⅰ and wave Ⅴ at rightear in children athigh-blood-lead group were obviously longer than those at low-blood-level group.Linear regression analysis revealed that contr ibut ion of Pb-B level of umbilical cord to the latencies of waves Ⅰ、Ⅲ and Ⅴ at rightear was still statistically significant after adjusting other confounding factors.Conclusion Low-level lead exposure during pregnancy can do harm to auditory development in infants.