Pot Smoking in Pregnancy Tied to Stillbirth Risk
Finding may gain significance as legalization spreads across U.S., study author says
By Steven Reinberg
MONDAY, Dec. 9, 2013 (HealthDay News) -- Expectant mothers who smoke marijuana may triple their risk for a stillbirth, a new study suggests.
The risk is also increased by smoking cigarettes, using other legal and illegal drugs and being exposed to secondhand smoke. Stillbirth risk is heightened whether moms are exposed to pot alone or in combination with other substances, the study authors added.
"Even when [findings are] controlled for cigarette smoking, marijuana use is associated with an increased risk of stillbirth," said lead researcher Dr. Michael Varner, associate director of women's health, obstetrics and gynecology at University of Utah School of Medicine.
Stillbirth refers to fetal death after 20 weeks of pregnancy.
Among drugs, signs of marijuana use was most often found in umbilical cord blood from stillborn infants, Varner noted.
"Because marijuana use may be increasing with increased legalization, the relevance of these findings may increase as well," he added.
Indeed, this seems likely as the push to legalize marijuana has gained momentum. Colorado and Washington state voted for legalization of marijuana and states including California, Connecticut, Maine, Nevada and Oregon are legalizing its medical use. In addition, these and other states, including New York and Ohio, are decriminalizing its use.
"Both obstetric care providers and the public should be aware of the associations between both cigarette smoking, including passive exposure, and recreational/illicit drug use, and stillbirth," Varner said.
Although the numbers were smaller for prescription narcotics, there appears to be an association between exposure to these drugs and stillbirth as well, he said.
While the study found an association between use of marijuana, other drugs and tobacco by pregnant women and higher risk of stillbirth, it did not establish a cause-and-effect relationship.
The report appears in the January issue of Obstetrics & Gynecology.
Study senior author Dr. Uma Reddy, a medical officer at the U.S. National Institute of Child Health and Human Development, said the reason why marijuana may increase the risk for stillbirths isn't clear.
"We don't know, but it's clear there is an increased risk of stillbirth with marijuana. Some of it is overlapping with smoking cigarettes, and we know that cigarette use is also associated with stillbirth," she said.