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EXPOSURE TO LEAD IN PREGNANCY

Date of issue: August 2023, Version: 3

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A corresponding patient information leaflet on EXPOSURE TO LEAD IN PREGNANCY is available.

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 pica. Lead crosses the placenta with cumulative uptake into the fetus.

Several key studies investigating the fetal risks associated with gestational exposure to lead assess lead exposure as a continuous variable. Therefore, where associations with adverse outcomes are observed, these studies describe a correlation between increasing lead concentrations and higher risks of the outcome rather than a specific concentration at which the risk is increased. As such, it is not generally feasible to define a safe maternal lead concentration in pregnancy. Additionally, several studies describing adverse effects have defined these with lead concentrations lower than those necessitating consideration of chelation therapy.

Although available epidemiological data are generally limited and confounded, currently available evidence suggests that miscarriage, 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 preeclampsia/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 miscarriage 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.

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from UKTIS.org to ensure you are using the most up-to-date version.