Concerns over prescribed opioid use among pregnant women

"The steep increase in the number of opioid prescriptions dispensed in the United States has been associated with a parallel rise in their misuse, fatal overdoses, and heroin use," she explains. "More recently, attention has been focused on the large increase in the number of infants born with neonatal abstinence syndrome."

In the US, estimates suggest that 14-22% of pregnant women receive an opioid prescription during their pregnancy, and there has been an increase in the prevalence of opioid use disorders among pregnant women.

Furthermore, the incidence of neonatal abstinence syndrome increased from 1.20 to 3.39 per 1000 live births between 2000 and 2009.

"High prescribing rates of opioids to women during pregnancy have probably contributed to recent increases in neonatal abstinence syndrome," argues Volkow.

Neonatal abstinence syndrome is a serious medical condition that results from a newborn who was exposed to addictive illegal or prescription drugs while in the mother's womb.

The potential effects of opioid exposure on the fetal brain are unknown, but studies in rodents have linked it to birth defects in the central nervous system. Furthermore, human epidemiological studies have found an association between opioid use during pregnancy and neural tube defects and other birth defects.

Studies have also indicated that opioid exposure could disrupt attachment between mother and baby, and cognitive impairments have been reported in children and young people born to women who misused opioids during pregnancy.

Opioids should only be prescribed to pregnant women with severe pain that cannot be controlled with less harmful treatments, Volkow recommends, and ideally be limited to a short term use to reduce the risk of associated harms.

However, she adds that if long term use is unavoidable, such as for women in need of treatment for heroin addiction, then careful assessment and monitoring should be carried out to reduce the risk of overdose, misuse and neonatal abstinence syndrome.