X-ray of a stillborn child with anencephaly, a neural tube defect where the brain and top of skull do not form. (Image: Lucien Monfils / Wikimedia)In August of 2012, Sara Barron alerted the Washington State Department of Health of an unusual situation at Prosser Memorial Hospital in the farm town of Prosser, Washington. A veteran nurse, Barron was in charge of infection control and quality assurance at the hospital when she noticed there had been two babies born with the birth defect of anencephaly in a six month period. When she discussed this with another doctor at the hospital, which averages 30 births per month, the doctor informed her that another baby with the defect was to be born soon.

Anencephaly is a serious birth defect in which a baby is born without parts of the brain and skull. It is a type of neural tube defect (NTD) that happens during the first month of pregnancy, usually before a woman knows she is pregnant. In normal development, “as the neural tube forms and closes, it helps form the baby’s brain and skull (upper part of the neural tube), spinal cord, and back bones (lower part of the neural tube). Anencephaly happens if the upper part of the neural tube does not close all the way, often resulting in a baby being born without the front part of the brain (forebrain) and the thinking and coordinating part of the brain (cerebrum). The remaining parts of the brain are often not covered by bone or skin.”

Almost all babies with the defect die shortly after birth.

In her more than 30 year career, Barron had only seen one or two cases of anencephaly. When she later attended a regional medical conference, she started hearing about more cases, in addition to the three at her hospital. It was then she realized there was a problem and she notified the state health department.

An investigation discovered that in 2012, there were 12 births with the defect. The investigation was expanded, and as of September 2013, 23 babies with anencephaly had been born since 2010 in the small three county area. Four were born with another neural tube defect (NTD), spina bifida. This means that for every 10,000 births, 8 were born with anencephaly, four times the national average of 2 for every 10,000. This just includes births as there could have been more NTD pregnancies that were terminated once the defect had been discovered.

It was obvious there was a cluster of defects. The question was, why?

In February 2013, a case study was done by reviewing the records and backgrounds of the women that had the 27 NTD pregnancies and compared them with another randomly selected 108 pregnant women from the same time period. They examined everything from where the women worked, where they were treated, lived, age, smoking habits, and even economic and educational factors. They also looked at race as there is a high migrant farm worker population in the area.

In a report published by the Centers for Disease Control in September 2013, they noted that, “No statistically significant differences were identified between cases and controls, and a clear cause of the elevated prevalence of anencephaly was not determined.”

Previous research has shown that low intake of folic acid before pregnancy and during the early stages of pregnancy increases the risk of NTD. Since 1996, the United States has required manufacturers to enrich grains such as rice and those used in cereal with folic acid to help increase the amount childbearing aged women received. Since that time, there has been a 27 percent decrease in the number of NTD pregnancies. Other studies have shown a 50-75 percent decrease in NTD pregnancies with the use of folic acid supplements.

With no clear indication of the cause of the cluster, the Washington State Health Department is stepping up efforts to have doctors educate their patients of the importance of folic acid for women prior to and during pregnancy. In addition, they are monitoring the nitrates concentration in private wells, as they are known to cause health issues and deplete the amount of folic acid in the body. The affected area is a farming community and nitrates are found in fertilizer.

The CDC continued to monitor the situation throughout 2013 and will issue an updated report in the spring.