EXPOSURE TO NERVE AGENTS IN PREGNANCY
(Date of issue: December 2017, Version: 1)
Organophosphate (OP) nerve agents are HIGHLY TOXIC acetylcholinesterase (AChE) inhibitors. There are two main classes of nerve agent: G-series nerve agents (NATO designation) include tabun (GA), sarin (GB), soman (GD) and cyclosarin (GF), and V-series agents include VG and VX.
There is limited published experience of confirmed OP nerve agent exposure in human pregnancy. The available data currently consists of one small case series of five pregnant women exposed to sarin at various stages of pregnancy. No evidence of adverse fetal effects were described in this case series, though only one woman was exposed during the period of organogenesis and no major symptoms of toxicity were reported, indicating limited exposure. Evidence from preclinical animal studies does not indicate that OP nerve agent exposure in pregnancy results in reproductive toxicity or teratogenic effects, even at maternally toxic doses.
In all cases of OP nerve agent exposure in pregnancy, maternal toxicity is likely to be a major determinant of risk to the fetus. However, due to the limited data concerning the teratogenicity of OP nerve agents, the absence of maternal toxicity does not exclude the possibility of adverse fetal effects. Where maternal treatment of OP nerve agent poisoning is required, this should be as for the non-pregnant patient. While there are limited data concerning the safety of maternal pralidoxime and atropine use in human pregnancy, where indicated, these should not be withheld on the account of pregnancy. In cases where OP nerve agent exposure occurs close to term or delivery, neonatal toxicity may arise. Owing to the lack of available evidence, close monitoring of the neonate is recommended in all cases of maternal OP nerve agent exposure in pregnancy.
Due to the lack of data, where exposure to OP nerve agents has occurred, even in cases which did not result in maternal toxicity, enhanced fetal monitoring may be warranted and should be considered on a case-by-case basis. Other risk factors may also 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. Discussion with UKTIS is recommended for all cases of exposure.
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