Despite alarms raised by local health care professionals, little information is available on an apparent cluster of neural tube defects (NTDs), including anencephaly-a fatal condition in which infants are born without parts of the brain or skull-in central Washington State that began in 2010.
According to media reports, it was Sara Barron, a veteran nurse at Prosser Memorial Hospital in Prosser, Washington, who first noticed the uptick in babies born with NTDs and notified the Washington State Department of Health (DOH). The department investigated and identified 27 NTD-affected pregnancies in Yakima, Benton, and Franklin counties from January 2010 to January 2013. Twenty-three of the infants were affected by anencephaly, three with spina bifida, and one with encephalocele. The anencephaly rate is the most alarming: 8.4 cases per 10,000 live births, four times the national average.
Working in conjunction with local officials and the Centers for Disease Control and Prevention, the DOH compared the demographic information and medical records of affected mothers with those from a control group of 108 randomly selected mothers who had healthy pregnancies and received prenatal care at the same clinics to determine causal factors. A report on the study was published in the September 6, 2013, Morbidity and Mortality Weekly Report. The data they examined included health conditions, weight, smoking, alcohol use, prenatal medication and supplementation (including folic acid), sociodemographic characteristics, and occupations. Home addresses were used to determine whether drinking water came from a public source or a private well. All findings were inconclusive: no significant differences were found between the control group and the affected population.
Medical records alone don't tell a complete story, however, and a number of news outlets have recently featured frustrated mothers wondering whether and when health officials would be interviewing them to examine possible environmental factors. "I can understand the frustration," says Susie Ball, genetics counselor at Yakima Valley Memorial Hospital. "But on the other hand, there's so much we don't know [about the cause of NTDs], I don't know how they'd narrow down the questions to ask."
NTDs have been linked to a lack of folic acid in the mother's diet, certain medications, and risk factors such as diabetes and prepregnancy obesity, as well as to genetic predisposition. Environmental factors, including exposure to certain chemicals, pesticides, hazardous waste, and nitrates in drinking water, have also been found to play a role. Still, much remains a mystery.
There has been anecdotal evidence of additional NTD cases recently (Ball herself recalls reporting "about a half dozen" NTDs found during pregnancy in 2013), but no official numbers are available yet. According to a DOH spokesperson, the investigation continues and data from 2013 are still being processed.
In the meantime, official recommendations on preventing NTDs include folic acid supplementation (400 to 1,000 micrograms daily in women of childbearing age), prompt and regular prenatal care, and annual testing of private well water. Where excessive levels of nitrates and bacteria are found in the water, an alternate source of drinking water should be used.-Laura Wallis