EXPOSURE TO LEAD IN PREGNANCY

Exposure to lead during pregnancy is rare, but may occur via occupational exposure, use of lead-containing cosmetics or traditional medicines, exposure to lead paints, and ingestion as a result of maternal pica. Lead crosses the placenta with cumulative uptake into the fetus.

Although available epidemiological data are generally limited and confounded, currently available evidence suggests that spontaneous abortion, impaired intrauterine growth, premature rupture of membranes and/or preterm labour, reduced infant head circumference, and impaired postnatal neurodevelopment may be associated with maternal exposure to elevated lead levels during pregnancy.

The currently available data on the risk of major congenital malformation in the infant following gestational exposure to lead are extremely limited. Possible associations between neural tube and heart defects and higher maternal levels of lead have been reported in small single studies with methodological limitations. Higher placental and cord lead concentrations have also been associated with late fetal deaths in a single study.

Maternal hypertension has also been linked to gestational lead exposure.

Where lead exposure has occurred during pregnancy, it is essential to identify the source and minimise further contact. There is very limited published information on which to base an assessment of the safety of chelating agents in pregnancy, however chelation therapy should not be withheld if clinically indicated. Guidance on the treatment of lead poisoning in pregnancy is available as a separate UKTIS monograph.

There are a number of reports suggesting adverse reproductive effects in men working with lead, some of which suggest an association with spontaneous abortion and impaired fetal growth.
Exposure to lead at any stage of pregnancy would not usually be regarded as medical grounds for termination of pregnancy, however additional monitoring of fetal growth may be advisable. Other risk factors which may independently increase the risk of adverse pregnancy outcome may also be present in individual cases. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.