Cadmium and pregnancy: a toxic mix

This blog was inspired by one of our team members who has long been concerned about the heavy metals that accumulate in the soil around industrial sites.. Industries like textiles, petrochemicals and tanneries can all leave heavy metals in the soil. In turn, vegetables absorb the heavy metals, like cadmium, and they end up in the bloodstream of the population.

Although heavy metals are naturally found in the earth's crust, certain human activities have changed their normal biochemical balance, thereby increasing their accumulation in the environment. Some heavy metals are an important constituent of enzymes and are therefore required by living organisms in small amounts; iron, molybdenum, cobalt, copper, zinc and manganese are specific examples of such metals. Other heavy metals have no known benefit on living organisms and are known to be toxic even in small amounts, examples of these are cadmium, lead, mercury and plutonium. 

Cadmium, in particular, is a toxic heavy metal that has no known benefits to humans. It poses a major public health issue to living organisms, and it particularly has detrimental effects on the reproductive system of females. The most common sources of cadmium exposure are green leafy vegetables and grains, as cadmium is accumulated from contaminated water and soil. Cigarette smokers are at a greater exposure risk to cadmium due to cadmium being naturally accumulated in the tobacco plant. As cadmium accumulates over time, it essentially means that the older you are, the more cadmium you have stored in your body. When cadmium exposure is high, it increases cellular oxidation products that deplete antioxidants like glutathione peroxidase and superoxide dismutase, rendering the body defenseless to further oxidative damage. 

Some effects of cadmium on female reproduction include delay in puberty and/or menarche, pregnancy loss, disorders of the menstrual cycle and reproductive hormones and premature birth and reduced birth weights. The female reproductive system is highly susceptible to damage by cadmium. The body burden of cadmium in females, especially those with iron deficiency, is generally higher than in males. The duodenal iron transporter is upregulated by iron deficiency which leads to an elevated absorption of dietary cadmium by the intestines. 

Cadmium can also suppress the pregnancy hormone, progesterone, preventing its role of sustaining pregnancy especially in the first 13 weeks of gestation leading to miscarriages. Cadmium can cause miscarriages through its ability to cross the placental barrier, accumulate in fetal tissues, and thereby hindering the major functions of the placental; like hampering its roles of signaling, transport of nutrients, cellular growth and maturation, secretion of hormones and enzymes.  

As one study of 85 other studies on heavy metals in pregnancy states, “It may be worthwhile for toxicologists and scientists in [sub-Saharan Africa] SSA to investigate if these heavy metals can become additional biomarkers in the diagnosis of miscarriages andstillbirths.” With greater knowledge on the effects of heavy metal toxicity, clinicians can better diagnose miscarriages. Maternova will keep our audience up to date on any additional news or studies that surface regarding cadmium and its effects on women and childbirth. 

Shae Janiga and Atanur Arapoglu

Sources:

https://www.sciencedirect.com/science/article/pii/S1110569017300377

https://www.ncbi.nlm.nih.gov/pubmed/18367374

https://pprc.org/wp-content/uploads/2017/07/Cd-in-Fertilizer_Reducing-Cd-Exposure-Gardens_Final_7-17-17.pdf

UN Photo/Eskinder Debebe

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