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

BACKGROUND: Lead 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. OBJECTIVES: To 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 METHODS: This 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. RESULTS: The 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 (r(s) = 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. CONCLUSIONS: The 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.