(Reuters Health) - A growing number of American pregnant women are using opioids and methamphetamines, and drug use is rising fastest among mothers in rural communities, a U.S. study suggests.

Nationwide, between 2008-2009 and 2014-2015, the proportion of babies born exposed to amphetamines - mostly meth - doubled from 1.2 infants for every 1,000 hospital births to 2.4 infants out of every 1,000 hospital births, the study found. By the end of the study period, the highest proportion of babies exposed to meth was in the rural West, where 11.2 babies in every 1,000 were exposed to amphetamine.

From 2004-2005 to 2014-2015, opioid use among pregnant women quadrupled, from 1.5 infants for every 1,000 hospital births to 6.5 babies out of every 1,000 hospital births, the study also found. By the end of the study period, the highest proportion of babies exposed to opioids was in the rural Northeast, where 28.7 in every 1,000 babies were exposed to opioids.

For pregnant women with amphetamine use, the risk of severe maternal complications and fatalities was 1.6 times higher than with opioid use, researchers report in the American Journal of Public Health.

“In addition to the important efforts going toward treatment of opioid use in pregnancy, the maternal health community should direct attention going forward toward the use of amphetamines as well,” said lead study author Dr. Lindsay Admon of the University of Michigan in Ann Arbor.

Complications like preterm deliveries, dangerously high blood pressure, heart failure, heart attacks, and blood transfusions were all more common among pregnant women who used amphetamines than pregnant women who used opioids, the study found.

There are treatments that can counter the effects of opioids, but nothing can block the effects of amphetamines, the study authors note.

Amphetamine use can cause vasoconstriction, or tightening of the blood vessels. In addition to complications for mothers, this can also restrict fetal growth and increase the risk of neurological problems for infants.

The analysis included about 47 million deliveries at U.S. hospitals. An estimated 82,254 deliveries included one or more amphetamine use diagnoses, and 170,164 included one or more opioid use diagnoses.

Pregnant women who used these drugs were more likely to be white, from lower-income communities and insured by Medicaid or other public health programs.

Costs for delivery hospitalizations were higher with drug use, the study also found. For women using amphetamines, the average cost was $5,700, compared with $5,400 for women using opioids and $4,600 for other hospital deliveries.

The study can’t prove whether or how drug use might directly impact health outcomes or costs of care for mothers or babies. It’s also possible that results from hospital deliveries don’t reflect what would happen for women who deliver babies in other settings, although most U.S. babies are born in hospitals.

Even so, the results show that the opioid crisis isn’t the only drug problem impacting maternal and child health in the U.S., said Joshua Brown of the University of Florida College of Pharmacy in Gainesville.

“As a nation, we have been very focused on opioids and neonatal alcohol syndrome in newborns,” Brown, who wasn’t involved in the study, said by email.

“This research is a reality check to recall that there are other substances of abuse that are being used by pregnant mothers,” Brown added. “Given the disproportionate burden of substance use disorders in rural areas, there’s a tremendous need for access to treatment options, screenings, and outreach to reduce all substance abuse during pregnancy whether that be prescription or illicit use of amphetamines, opioids, cannabis, tobacco, etc.”

SOURCE: bit.ly/2FWCJgw American Journal of Public Health, online November 29, 2018.