Very little is known about chromium and pregnancy, and even the general daily recommended amount of chromium is debated. However, current research suggests that supplementation is not necessary during pregnancy, and adult women are estimated to consume enough chromium through a varied diet.
Although chromium is widely known for its potential glucose tolerance effects in individuals with diabetes, this popular health claim remains unproven, and is still being studied regarding gestational diabetes.
Women should not take any chromium supplementation for any reason without speaking to their health care provider (HCP).
Note: Pregnant women can be exposed to environmental chromium through private drinking wells or through their employment (auto/metal). Women who have concerns regarding this exposure should read the below and talk to their HCP about steps they can take to limit their exposure during pregnancy.
Background
Chromium is an essential element and metal naturally dispersed in the environment. Chromium is primarily in two forms: one required by humans in dietary form and another that is considered a toxic metal:
The dietary form of chromium is directly involved in carbohydrate, fat, and protein metabolism, may have an impact on insulin, and is only needed by humans in trace amounts.
Most knowledge concerning the effect of chromium exposure on health has been based on data from individuals exposed to chromium through their employment/occupation.
It is estimated that 10 million Americans take supplemental chromium, making chromium the second largest-selling mineral supplement after calcium. It is popular for optimal insulin function and diabetes management. It is also believed to help athletes create lean body mass; however, both of these claims are controversial.
Pregnancy
Research regarding chromium’s role during pregnancy is difficult as it is not known whether chromium levels in the blood accurately reflect chromium status during pregnancy.
Some researchers believe more chromium is needed during pregnancy since the mother’s storage of chromium is depleted, and that supplementation could prevent deficiency problems.
One study provided evidence of increased chromium loss in at least 22% of women experiencing a healthy pregnancy.
The role of chromium supplementation in gestational diabetes is being studied but is not currently recommended as a management method due to mixed results on positive effects. Further, it could change the amount of insulin required by some women.
The hypothesis that chromium supplementation can help with glucose tolerance in diabetes is popular, based on individuals who developed diabetes when they had no chromium in their diet. Their condition was essentially cured when given chromium supplementation.
However, these results have not translated to individuals with diabetes who have no chromium deficiency, and chromium has very little effect on glucose tolerance in those cases.
Chromium does cross the placenta, and high environmental chromium exposure (such as in drinking water or through occupational exposure) has been linked to negative outcomes such as preterm birth, impaired fetal development, and birth defects.
In 2010, an American environmental organization studied the drinking water in 35 American cities and found that at least 74 million people in nearly 7,000 communities drink tap water containing elevated chromium levels (caveat: chromium levels are hard to measure in these kinds of tests).
Public water systems are tested to ensure they conform to certain drinking water standards, but there are no requirements about the testing of private wells. Local county environmental health departments can refer individuals to a certified laboratory that will test well water for chemicals. For more information, click here (EPA) (also see Resources, below).
Supplementation
Not all prenatal vitamins contain chromium; if they do, it is usually above the daily requirement (which is controversial) of 20 to 30 micrograms (mcg)/day for pregnant women.
Some recommendations have indicated that greater doses of chromium may be required to observe beneficial effects during pregnancy, but research remains incomplete and inconsistent.
It is estimated that adult women in the United States consume about 23 to 29 mcg/day of chromium from food, which is currently within recommendations.
An upper daily limit has not been established, as very few negative effects have been reported. However, women should never take any supplements during pregnancy without first speaking to their HCP. Further, chromium may decrease or enhance absorption of certain medications.
Food Sources
Chromium is found in foods such as tomatoes, liver (limit due to high amounts of vitamin A), cheese, meats, potatoes, egg yolk, fish, fruits, vegetables, and whole grains.
Action
Pregnant women should never take any form of supplementation without speaking to their HCP first.
Women who were taking, or are currently taking chromium supplements while pregnant need to inform their HCP. Women should have a risks and benefits discussion with their HCP regarding the continued use of chromium.
Women who consume drinking water from private wells may wish to have their water tested for various contaminants (see Resources).
Women who believe they are exposed to high levels chromium or other metals as a part of their employment should talk to their HCP, as well as their employer. HCPs can provide medical notice to employers that a pregnant woman's role should be temporarily changed or accommodated for both the health of her and her baby (Occupational Safety and Health Act of 1970).
Resources
For more information regarding drinking water and having a well tested for chromium levels and other contaminants, visit the below links or call the local health department or the EPA Safe Drinking Water Hotline at (800) 426-4791.
Reproductive Health and the Workplace: Heavy Metals (Centers for Disease Control and Prevention)