USE OF DMSA IN PREGNANCY

Dimercaptosuccinic acid (DMSA) is an organosulfur antidote used orally in the treatment of heavy metal poisoning; particularly lead and arsenic.  There are insufficient published data available to provide a risk assessment on the potential effects following exposure to DMSA in pregnancy.  Where maternal toxicity occurs following heavy metal poisoning, there is a potential for fetal toxicity.  In cases of severe maternal systemic poisoning, it is important to treat the mother appropriately to reduce the risks of maternal and fetal toxicity.

The antidotes used in the treatment of heavy metal poisoning are not without risk and may offer only limited benefit in reducing fetal exposure when used during pregnancy.  There is also a risk that maternal chelation therapy will result in mobilisation of the heavy metal from the mother into fetal tissue.  It is therefore recommended that guidelines for non-pregnant adults should be followed in the pregnant patient, with chelation therapy reserved for patients with severe toxicity.

Alternative chelating agents to DMSA may be recommended as first-line treatment of heavy metal poisoning.  Where DMSA is required in the management of severe poisoning then treatment should not be withheld at any stage of pregnancy.  Discussion with UKTIS is recommended in all cases where chelation therapy is being considered.

Exposure to DMSA at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy. However other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case specific risk assessments. Enhanced antenatal surveillance may be warranted and should be decided on a case-by case basis.