EXPOSURE TO ARSENIC IN PREGNANCY

Metallic arsenic (As) 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 (APL) where previous treatment with retinoids has failed.

Data regarding therapeutic use of arsenic trioxide in pregnancy to treat APL are limited to a very small number of uncontrolled case reports, all exposed after the first trimester. While routine use cannot be recommended, its use can be considered during pregnancy if there is no suitable alternative treatment.

Data are available regarding environmental arsenic exposure in pregnancy but are likely to be of limited value for assessing the risks associated with therapeutic or acute arsenic exposure in pregnancy. With acute arsenic exposure, the risk of fetal toxicity is likely increased with maternal toxicity.

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, miscarriage, stillbirth, small for gestational age, preterm birth risks, and neonatal/childhood complications, including infections, neurodevelopmental impairments and morbidity. 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.