NIH Report: Tobacco, Drug Use in Pregnancy Can Double Risk of Stillbirth
Researchers document increased risk associated with marijuana, other substances (December 11)
Smoking tobacco or marijuana, taking prescription painkillers, or using illegal drugs during pregnancy is associated with double or even triple the risk of stillbirth, according to research funded by the National Institutes of Health.
Investigators based their findings on measurements of the chemical by-products of nicotine in maternal blood samples, and of cannabis, prescription painkillers, and other drugs in umbilical cords.
The study, published in Obstetrics & Gynecology, involved women who delivered between March 2006 and September 2008 at 59 hospitals in the Stillbirth Collaborative Research Network.
The researchers tested the women’s blood for cotinine, a derivative of nicotine, and tested fetal umbilical cords for evidence of several types of drugs. They looked for evidence of the stimulants cocaine and amphetamine; prescription painkillers, such as morphine and codeine; and marijuana. These tests reflected exposure late in pregnancy.
Based on the blood test results and the women’s responses, the researchers calculated the increased risk of stillbirth for each of the substances they examined:
- Tobacco use: a 1.8 to 2.8 times greater risk of stillbirth, with the greatest risk found among the heaviest smokers
- Marijuana use: a 2.3 times greater risk of stillbirth
- Evidence of any stimulant, marijuana, or prescription painkiller use: a 2.2 times greater risk of stillbirth
- Passive exposure to tobacco: a 2.1 times greater risk of stillbirth
“Smoking is a known risk factor for stillbirth, but this analysis gives us a much clearer picture of the risks than before,” said senior author Uma M. Reddy, MD, MPH. “Additionally, the latest findings also showed that likely exposure to secondhand smoke can elevate the risk of stillbirth.”
Reddy added, “With the legalization of marijuana in some states, it is especially important for pregnant women and health care providers to be aware that cannabis use can increase stillbirth risk.”
Source: NIH; December 11, 2013.