State finds no single cause of Benton, Franklin fatal birth defects

After an almost two-year investigation, the state Department of Health has concluded that there is no sole factor to blame for a cluster of fatal birth defects in Benton, Franklin and Yakima counties between 2010-16, according to a report released last week.

However, medical records showed women in the three counties were getting lower levels of folic acid early in their pregnancy than women in the rest of the state.

In that six-year period, according to the department, 45 babies in the three counties were born with anencephaly, a neural tube defect that is uniformly fatal.

They included 19 babies in Benton County, five in Franklin County and 21 in Yakima County.

Anencephaly affects fetuses within the first few weeks of pregnancy, and causes them to be born missing pieces of their skull and brain and without a fully-developed neural sac to protect the spinal cord. Babies born with anencephaly die within hours or a few days.

“Neither the descriptive epidemiology of the anencephaly-affected pregnancies; the medical records-based case-control study of pregnancies from January 2010-January 2013; interviews of mothers of (neural tube defect)-affected pregnancies; nor investigation of community concerns identified a preventable cause for most of the NTD-affected pregnancies,” the department’s report said.

After consulting with public health officials involved in researching the cause of the cluster, the Department of Health suspended its investigation in late 2016 and is now focusing on surveillance, outreach and prevention, the report said.

The average national rate of the defect is two out of every 10,000 babies. The Yakima-Benton-Franklin rate was four times that — more than eight of every 10,000 babies affected between January 2010 and September 2016.

The study concluded that the difference in rates may be exaggerated by more complete reporting in the three-county area than elsewhere in the country, but that even accounting for the reporting difference, the birth defect rate in the Mid-Columbia was higher than usual.

A major factor identified by public health officials — in this investigation and in established literature on anencephaly — is a mother’s folic acid intake prior to and in the first several weeks of pregnancy.

Women in the Yakima-Benton-Franklin county area, including those with normal pregnancies and with pregnancies affected by a birth defect, had low folic acid intake compared with women in the rest of Washington, the report said.

Folic acid is found in leafy green vegetables, citrus fruits, beans and grain-based food like bread, rice, cereal and pasta, because white flour is fortified with folic acid.

In 2016, the Food and Drug Administration approved folic acid fortification of corn masa flour, which public health officials hope will improve folic acid intake for Hispanic women who use masa flour in cooking.

That’s important because Hispanic women are more likely to be affected by anencephaly: The report shows that between 2010-15, the rate of anencephaly was 9.6 per 10,000 births among Hispanic or Latina women, 50 percent higher than the rate of 6.4 per 10,000 births among non-Hispanic white women.

Hispanic women accounted for almost two-thirds of anencephaly cases in the cluster, but only about 56 percent of total births for that time frame.

Responding to concerns from community members, the Department of Health spent part of its investigation looking into whether nitrates in drinking water played a role in the birth defect cluster.

Investigators mapped mothers’ addresses to assess whether they were on private or public water systems, then looked up available water testing results for the months immediately preceding and following conception in cases of anencephalic births.

Investigators determined that even on private water systems, nitrate levels “continued to be well below 5 mg/L,” the level at which nitrates in the water are considered dangerous.

“In summary ... drinking water nitrate levels were not elevated among women with anencephaly- or NTD-affected pregnancies in the three-county area,” the report said.

Investigators also looked into community concerns of pesticide exposure, but found no history of pesticide drift involving the chemicals most likely to influence anencephaly.

Mapping mothers’ residential proximity to fields that use pesticides didn’t turn up a smoking gun, either, as a majority of both women with healthy pregnancies and women with anencephalic births in the three-county area live near agricultural operations.

The possibility that radiation from the Hanford nuclear reservation or from the Fukushima nuclear disaster might have contributed to the cluster was ruled out. Investigators consulted Department of Health staff responsible for collecting radiation and radioactive contamination data, including checking for contamination in the air and the Columbia River near Hanford.

Several other factors also were considered in the investigation.

Since summer 2014, the Department of Health has been working with March of Dimes and other health care partners on outreach to increase prenatal use of folic acid supplements, “because this is the only known way to effectively prevent (neural-tube defects),” the report said.

Efforts are aimed at all women of childbearing age, because folic acid intake affects the health of a pregnancy before most women are even aware they’re pregnant.

The Tri-City Herald contributed to this report.

This story was originally published September 17, 2017 at 11:08 AM with the headline "State finds no single cause of Benton, Franklin fatal birth defects."