Arsenic Exposure May Impact Fetal Development; Linked To Low Baby Weight, Smaller Head Circumference

newborn
Even low levels of arsenic exposure during pregnancy may impact fetal growth, though this may be modified by the mother’s weight and the sex of the baby. Getty Images

From the time of the Roman empire, arsenic has been considered an ideal poison due to a lack of color, odor, or taste when mixed in food or drink; since the symptoms mimic food poisoning, it is also difficult to detect. Now researchers from Dartmouth College question whether prenatal exposure to this subtle poison harms the health of infants.

Their study results suggest even low levels of arsenic exposure during pregnancy may impact fetal growth, though this may be modified by the mother’s weight and the sex of the baby.

The Environmental Protection Agency classifies arsenic as a cause of cancer. While disease may be the most frightening potential effect, the agency finds, over the long-term, exposure to arsenic may also lead to nausea, diarrhea, abdominal pain, anemia, and liver or kidney damage. The World Health Organization names arsenic among its “10 chemicals of major public health concern.” Yet arsenic naturally occurs throughout the environment, and most of our exposure, which is entirely unintentional, comes from food. In rural areas, there is one other common risk to consider.

“Arsenic is [also] naturally occurring in groundwater, and women in rural areas who rely on well water, which is unregulated, may be exposed through their drinking water,” Dr. Diane Gilbert-Diamond, an assistant professor of epidemiology, told Medical Daily.

Scientists also know that arsenic passes from mother to unborn child after crossing the placenta. A previous Dartmouth medical school study of 766 women showed total arsenic concentrations in placental samples corresponded to levels found in the mother’s urine during pregnancy, in the toenails of both mother and child, and in household drinking water. A separate research effort led by Dr. Margaret Karagas, chair of epidemiology at Dartmouth’s Geisel School of Medicine, indicated high levels of arsenic in a mother’s urine during her second trimester of pregnancy are linked to decreased head circumference at birth.

For the current study, a science team led by Karagas and Gilbert-Diamond investigated whether a mother’s weight and the infant’s sex might modify the effects of prenatal arsenic exposure, so they examined the medical records of 706 mother-infant pairs.

Prenatal Exposure, Postnatal Effects

The records contained in utero arsenic exposure as measured by each mother’s second trimester urine test. (During this trimester, the baby’s already functioning organs, nerves, and muscles continue to develop and grow, according to the Mayo Clinic, while the baby begins to form bones, accumulate fat, move, and develop hearing.) The researchers also analyzed each mother’s weight gain during pregnancy in addition to the quality of the infants’ health at birth.

They found that a mother’s arsenic levels during the second trimester were connected to her baby’s weight, head circumference, and length at birth, yet these relationships varied depending on the mother’s BMI and the newborn’s gender.

Each doubling of total arsenic exposure was associated with a 0.10 cm decrease in head circumference, a 0.15 cm increase in birth length, and a lower birth weight. However, the researchers observed this connection between arsenic exposure and birth length in boy babies only. Similarly, each doubling of total arsenic was related to lower birth weight in girls born to overweight or obese mothers, while children born to normal weight mothers showed no effect or even the opposite.

Overall, these differences are small, yet they might lead to big effects in how babies develop. For this reason, the researchers believe more research is needed to understand any possible long-term associations between prenatal arsenic exposure and pediatric health. In the meantime, these results should concern anyone who lives in regions where drinking well water is routine.

“It is important for all people who use well water to have it tested for arsenic and other contaminants to minimize their risk,” said Gilbert-Diamond.

Source: Gilbert-Diamond D, Emond JA, Baker ER, Korrick SA, Karagas MR. Relation between in Utero Arsenic Exposure and Birth Outcomes in a Cohort of Mothers and Their Newborns from New Hampshire. Environmental Health Perspectives. 2016.

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