Mercury exposure in the prenatal period is of great public health concern. Mercury has the ability to cross the placenta freely, accumulating more in the foetus. Having a predilection for the neuronal cells of the developing brain, prenatal mercury levels exceeding 5.8µg/L may lead to irreversible neurodevelopmental disorders in children. Several risk factors for mercury exposure have been identified globally, including fish consumption and use of skin-lightening creams and the populace in Lagos is exposed to a number of these factors. There is, therefore, a high possibility that mothers living in Lagos and their newborns may have high blood mercury levels. Aim and objectives:This study aimed to determine maternal and umbilical cord blood mercury levels, identify factors associated with toxic levels, assess the relationship between these levels and the maternal sociodemographic factors and assess the effects of elevated maternal blood mercury levels on newborn gestational age and anthropometry.