More Pregnant Women on Painkillers, Heroin: Study
U.S. national data shows steady rise, and abuse may pose dangers to mother and baby, experts say
However, the study has several limitations that should be considered, said Dr. Robert Newman, director of The Baron Edmond de Rothschild Chemical Dependency Institute at Beth Israel Medical Center in New York City.
"The study makes no distinction between dependence on appropriately prescribed, medically indicated opioids and that associated with self-administered opioids taken under potentially very hazardous circumstances," he said. "The different consequences for the expectant mother and unborn child are enormous."
For example, methadone or buprenorphine are both opioids that can be safely used in treatment of addiction, Newman pointed out. In fact, he said, methadone maintenance is the most effective known treatment for heroin addiction, including in pregnant women.
The study authors agreed that "we were not able to distinguish between women who were dependent on or abuse prescription opioids, those who were enrolled in opioid maintenance programs [e.g., with methadone or buprenorphine], and those who abused heroin."
However, women dependent on opioids were twice as likely to go into labor early, with 17 percent experiencing preterm labor versus 7 percent among those without opioid dependency. Women dependent on opioids were also 20 percent more likely to require a C-section and 40 percent more likely to have their water break early.
Two types of complications, intrauterine growth restriction and placental abruption, were also more likely -- though still rare -- in women dependent on opioids than not. Intrauterine growth restriction refers to a baby's poor growth in the womb and occurred in about 7 percent of those dependent on opioids and 2 percent of those without a dependency. Placental abruption, in which the placenta comes off the uterus wall before delivery, occurred in about 4 percent of women with opioid dependency and 1 percent of women without dependency.
The risk of stillbirth was also higher among those dependent on opioids, at a rate of 1.2 percent compared to 0.6 percent of stillbirths among mothers with an opioid dependency.
The risk of maternal death during delivery was also higher for mothers dependent on opioids. Although the risk remained very rare (20 of over 60,000 opioid-dependent pregnant women died), the risk was still more than four times that of nonaddicted pregnant women. Similarly, the risk of maternal heart attack was four times higher among women dependent on an opioid, the study found.