Newborn testing shows prenatal nicotine exposure higher than maternal reported rates

Monday, May 12, 2014

New U of M-developed assay method utilizes newborn dried blood spots for efficient, low-invasive testing 

New evidence out of the Masonic Cancer Center, University of Minnesota, shows more mothers are smoking while pregnant than is reported on their children’s birth certificates. The research was done using newly developed assay methods, allowing researchers to look at very small blood samples while maintaining accurate results.

The research was published online today in the journal Pediatrics. The principal investigator for the project was Anne Joseph, M.D., M.P.H.

The newly developed assay utilized newborn dried blood spots (DBS) obtained from four states that store and release the samples anonymously and for advancement of public health. The samples for this study were obtained with ethical approval from California, Michigan, New York and Washington.

“Prenatal exposure to tobacco smoke has been connected to both short- and long-term effects on babies, including lower birth weights, birth defects, asthma, and neurobehavioral problems,” said lead author Logan Spector, Ph.D., associate professor in the Division of Epidemiology and Clinical Research in the Department of Pediatrics, as well as a member of the Masonic Cancer Center. “These effects also don’t consider other potential lifetime risks, such as cancer.”

Current surveillance of maternal smoking rates rely heavily on information recorded on birth certificates, but this can be imprecise. Spector and his collaborators wanted an objective way to determine smoking rates among pregnant women.

Utilizing a newly-developed assay, researchers tested DBS for cotinine, a marker created by the body after exposure to nicotine. They found 12 percent of the DBS tested showed levels of testing indicating the mother had smoked within the last several days before giving birth. Of those testing positive, 41 percent of mothers were not noted to be smokers.

“The numbers we found were similar to other studies of socially disapproved behaviors during pregnancy, showing many women underreported their tobacco use to physicians or nurses,” said Spector. “Still, this number may underestimate the number of women who smoke late in pregnancy; our tests only show those babies exposed to tobacco products between three and five days prior to birth.”

The new assay, developed at the University of Minnesota by Sharon Murphy, Ph.D., helps collect quantitative data from small dried blood samples. Because it is not always feasible to collect plasma or other biological samples, and because of limits in storing or transporting such samples, alternative testing methods can be useful in collecting data with minimal intrusion and increased efficiency.

“This collection method may be particularly useful in low-resource nations or in data collection points where many participants will be sharing their samples,” said Spector. “Dried blood spots are hygienic, lightweight, and do not require refrigeration, as well as being non-invasive for participants. It’s a very efficient model for research.”

Funding for this project was supported by National Heart, Lung and Blood Institute grant 1RC2HL10140. Support was also provided by the Masonic Cancer Center, which is supported by CA-77598, and the National Institutes of Health.