EXPOSURE TO ARSENIC IN PREGNANCY

Metallic arsenic is used in the production of semi-conductors and in industrial processes for strengthening metals. Arsenic and its compounds may occur naturally in groundwater and are used in the production of pesticides, herbicides and insecticides, although this practice is decreasing. Arsenic trioxide is used to treat adult patients with relapsed/refractory acute promyelocytic leukaemia where previous treatment with retinoids has failed.

There are no data to assess the safety of the therapeutic use of arsenic trioxide in pregnancy, therefore its use cannot be recommended. However, if clinically indicated, maternal treatment should not be withheld on the basis of pregnancy.

The results of studies investigating the fetal effects of environmental exposure to arsenic through drinking water or air pollution during pregnancy are likely to be heavily confounded by unmeasured concomitant exposures and other lifestyle/sociodemographic factors. As such, it is difficult to attribute causality of any detrimental effects observed to prenatal environmental arsenic exposure alone. The results from these studies are also occasionally conflicting. Some studies have associated environmental exposure to arsenic through drinking water or air pollution during pregnancy with overall congenital malformation, cardiovascular malformation, spontaneous abortion, stillbirth, small for gestational age or preterm birth risks, and neonatal/childhood complications including infections, neurodevelopmental impairments and morbidity. Associations with decreased infant birth weight have also been demonstrated. Although dose-response relationships have been defined in some studies, a threshold dose above which risk of adverse fetal effects is increased remains to be defined. 

Acute maternal arsenic poisoning during pregnancy may result in maternal and/or fetal death. Owing to the potential severity of arsenic exposure, treatment during pregnancy should be the same as for the non-pregnant patient. Maternal toxicity is likely to be a major determinant of risk to the fetus following arsenic exposure.

Enhanced antenatal surveillance may be warranted and should be decided on a case-by-case basis. Discussion with UKTIS is recommended in all cases where exposure to arsenic has occurred at any stage of pregnancy.