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A paper in the current issue of Fluoride by Changalvala et al. reports a new finding of raised serum fluoride levels in pregnant women with pre-eclampsia. The authors found that pregnant women, at 20 or more weeks of gestation, with preeclampsia (n=150) in Karnataka, India, had significantly higher levels of serum fluoride (p<0.05) than a control group of pregnant women without pre-eclampsia (n=150) (1.8±0.66 and 0.18±0.31 mg/L, respectively). The question follows as to whether the association between a raised serum fluoride and pre-eclampsia is causal. The current knowledge on pre-eclampsia indicates that it is a complex multisystem disease. Central to the pathogenesis are abnormal placentation with uteroplacental ischaemia early in the first trimester and a hypertensive maternal syndrome with multi-organ failure, later in the second and third trimesters, with the release into the maternal circulation from the ischaemic placenta of soluble toxic and antiangiogenic factors, such as soluble fmslike tyrosine kinase (sFLT1) and soluble endoglin (sENG), which result in inflammation, endothelial cell dysfunction, and maternal systemic disease. The placental ischaemia may lead to small for gestational age babies. Various theories have been proposed to explain the condition. To help establish whether or not the relationship between fluoride exposure and pre-eclampsia might be one of causation rather than association, two of the nine Bradford Hill criteria establishing a causal relationship were considered. When coherence was examined with respect to low birth weight, the generally known facts of the natural history and biology of fluorosis, and pre-eclampsia, no serious conflict was found. The criterion of plausibility was examined by considering whether or not there were known effects of fluoride that might affect the pathophysiology as currently understood. The result was that it was considered plausible that fluoride might be able to affect the development of the disease. At present, on this basis, it is more likely than not that fluoride is a risk factor for the development of pre-eclampsia. However, the pathophysiology of pre-eclampsia is complex and will become clearer over time as more research is done. [ABSTRACT FROM AUTHOR]

A recent paper by Changalvala et al. reported finding significantly higher levels of serum fluoride (p<0.05) in 150 pregnant women, at 20 or more weeks of gestation, in Karnataka, India, with the complex multisystem disease of pre-eclampsia, than in a control group of 150 pregnant women without pre-eclampsia (1.8±0.66 and 0.18±0.31 mg/L, respectively). Whether the association between a raised serum fluoride and pre-eclampsia might be one of causation rather than association, has been discussed with respect to two of the nine Bradford Hill criteria for establishing a causal relationship, coherence and plausibility, and it was considered plausible that fluoride might be able to affect the development of the disease. Although a review by Rana et al. did not list lead as a risk factor for pre-eclampsia, this has been established in other studies and controlling for blood lead levels would be appropriate in future studies of the relationship between fluoride and pre-eclampsia. [ABSTRACT FROM AUTHOR]