Determination of lead levels in maternal and umbilical cord blood at birth at the Lagos University Teaching Hospital, Lagos

BackgroundLead toxicity is a cause of intellectual disability in children and majority of affected children live in developing countries. Its adverse effect on pregnancy outcome has also been documented.ObjectivesTo assess the relationship between maternal blood lead levels and umbilical cord blood lead levels in their corresponding newborn infants; to determine factors associated with high blood lead levels and the pregnancy outcome in participants.Materials and methodsThis was a cross-sectional descriptive study carried out at a tertiary Teaching Hospital, Lagos, Nigeria. Four hundred and forty pregnant women and their respective newborns delivered at the study centre. Blood samples were obtained from the mothers and umbilical cord of the newborns at delivery and analysed by atomic absorption spectrophotometry. Socio-demographic and obstetric data was obtained by questionnaires administered to the mothers. The anthropometric measurements of the babies were taken at birth and clinical data recorded. Main outcome measures were blood lead levels in mother and baby pair, socio-demographic factors, birth weight, gestational age, length, occipito-frontal circumference.ResultsThe median maternal and umbilical blood lead level was 64.3μg/dl and 39.2μg/dl respectively. The levels were above 5μg/dl in 75.6% and 66.8% of mothers and umbilical cord respectively. There was a strong positive correlation between the maternal and umbilical cord blood lead levels (rs = 0.80). Use of calcium supplements during pregnancy was significantly associated with a lower maternal blood lead level (p = 0.010) while recent painting and renovation of residential accommodation were associated with a higher umbilical cord blood lead level (p = 0.025). There were no statistically significant associations between the maternal and umbilical cord blood lead levels and the gestational age and anthropometry of the newborns at birth.ConclusionsThe blood lead levels in newborns of women residing in Lagos, Nigeria are high and administration of antenatal calcium is associated with lower blood lead levels.

背景 儿童铅中毒是引发智力残疾的重要病因，绝大多数受累儿童生活于发展中国家。现有文献亦已证实，铅暴露对妊娠结局具有不良影响。
目的 评估孕产妇血铅水平与其新生儿脐带血铅水平之间的相关性；明确研究对象中高血铅水平的相关影响因素及妊娠结局情况。
材料与方法 本研究为一项横断面描述性研究，于尼日利亚拉各斯的一所三级教学医院开展。研究纳入440名在该研究中心分娩的孕产妇及其对应新生儿。于分娩时采集孕产妇静脉血及新生儿脐带血样本，采用原子吸收分光光度法（atomic absorption spectrophotometry）进行铅含量检测。通过向孕产妇发放问卷收集其社会人口学及产科相关数据。于新生儿出生时测量其人体测量学指标，并记录临床相关数据。本研究的主要结局指标包括母婴配对血铅水平、社会人口学因素、新生儿出生体重、胎龄、身长及枕额周长。
结果 孕产妇及新生儿脐带血铅水平的中位数分别为64.3μg/dl与39.2μg/dl。其中75.6%的孕产妇、66.8%的新生儿脐带血铅水平高于5μg/dl。孕产妇血铅水平与新生儿脐带血铅水平呈显著正相关（rs=0.80）。妊娠期服用钙剂与孕产妇较低的血铅水平显著相关（p=0.010）；而近期居所粉刷及翻新与新生儿较高的脐带血铅水平相关（p=0.025）。孕产妇及新生儿脐带血铅水平与新生儿出生时的胎龄及人体测量学指标均无统计学意义上的显著关联。
结论 居住于尼日利亚拉各斯的孕产妇所分娩新生儿的血铅水平普遍偏高，且产前服用钙剂与较低的血铅水平显著相关。