University of Nevada, Reno researcher collaborates with local health community to look for answers to elevated incidence rate
Results of an investigation conducted by University of Nevada, Reno researchers, public health officials and area physicians published this week in the Archives of Pediatrics & Adolescent Medicine, indicate that Washoe County experienced a cluster of a particular birth defect, gastroschisis, during the period April 2007 - April 2008. Subsequent review of medical records since the study's conclusion indicates that while the rate is still elevated, the cluster appears to have subsided.
Gastroschisis is a birth defect that occurs early in pregnancy, characterized by incomplete closure of the baby's abdominal wall. It is most common in births by young women, age 21 or younger. Babies with this birth defect are born with part of their intestines outside their bodies, which necessitates repair of the abdominal wall in the first week of life.
The investigation concluded that a baby born in Washoe County during the one-year period of April 2007 to April 2008 was 10 times more likely to have gastroschisis than a baby born in any of the years from 1991 to 2005. There were 14 gastroschisis births in Washoe County during the one-year study period, and only 16 gastroschisis births in the County during the 15-year period of 1991 to 2005. Since April 2008, there have been five gastroschisis births in the County.
"While this is one of the largest documented gastroschisis clusters that I have found, and it is still a concern that requires further investigation, we are pleased the cluster seems to have subsided," said Leslie Elliott, assistant professor of epidemiology at the University of Nevada, Reno School of Community Health Sciences and principal investigator of the study. "And, most importantly, because mothers sought prenatal care, our excellent physicians in the community were able to diagnose the condition during pregnancy, and then plan for and provide the immediate care required at birth to correct it."
This study added significant support to the findings of other studies that certain infections, such as colds and sore throats; use of cold medications, such as pseudoephedrine; and some recreational drugs, may be contributing factors in the development of gastroschisis.
In this study, "case mothers," mothers who had babies with gastroschisis during the study period, were 13 times more likely to report having a sore throat during early pregnancy, and 17 times more likely to report having a chest cold in early pregnancy than "control-group mothers," those who did not have babies with gastroschisis during the study period. In addition, case mothers were nine times more likely than control-group mothers to report having taken over-the-counter medications for these infections during pregnancy.
Case mothers were more than four times as likely as control-group mothers to report use of at least one vasoconstrictive recreational drug before pregnancy. Vasoconstrictive recreational drugs constrict blood vessels and include methamphetamine, amphetamine, cocaine and Ecstasy.
This study is the first to find an association between gastroschisis and methamphetamine use, specifically. Case mothers were seven times more likely than control-group mothers to report methamphetamine use before pregnancy.
It is also important to note that some case mothers in the cluster did NOT report any of the identified risk factors.
Elliott was senior epidemiologist of chronic diseases with the Washoe County Health District and an adjunct faculty member of the University at the time the cluster surfaced.
"Local public health nurses and perinatologists noticed an increase in the number of babies being diagnosed with the defect in Washoe County, and reported this to us at the Epidemiology Division of the Washoe County Health District," Elliott explained.