About one out of every seven pregnant women in the U.S. was prescribed opioids for pain at some time during their pregnancy, according to the results of a surprising new study published in the journal Anesthesiology.
The study looked at a large database of over half a million pregnant women enrolled in an insurance plan who delivered their babies between 2005 and 2011.
Of the more than 530,000 pregnant women, 76,742, or 14.4%, were prescribed opioids, usually for less than a week. Nearly 6% of the pregnant women were prescribed opioids in the first and second trimester. In the third trimester, 6.5% took painkillers.
The study also found the use of opioids by pregnant American women was significantly higher than in Europe.
Opioid use also varied by region, ranging between 6.5% and 26.3%, with the lowest rates in the Northeast and the highest in the South. Arkansas, Mississippi and Alabama all had opioid prescription rates in excess of 20 percent.
“Nearly all women experience some pain during pregnancy,” said study author Brian Bateman, MD, Harvard Medical School. “However, the safety of using opioids to manage their pain remains unclear. Ultimately, we need more data to assess the risk/benefit ratio of prescribing these drugs to women and how it may affect their babies.”
Back pain was the most common condition (37%) for which opioids were prescribed, according to the study. Other conditions included abdominal pain, migraine, joint pain and fibromyalgia.
The most commonly prescribed opioids during pregnancy were hydrocodone (6.8%), followed by codeine (6.1%), oxycodone (2%) and propoxyphene (1.6%).
“The risk to the fetus of short-term exposure to prescription opioids under medical supervision is difficult to assess and needs to be carefully examined in future studies,” said Pamela Flood, MD, professor of anesthesiology, Pain and Perioperative Medicine at Stanford University.
Flood says previous studies have had contradictory findings regarding the risk to the baby. An early U.S. study (1959-1965), and later studies from Sweden and Norway, did not find an association between opioid prescriptions and birth defects.
However, a U.S. National Birth Defects Prevention Study (1997-2005) found associations between codeine and other opioids with birth defects, including atrial and ventricular septal defects, hypoplastic left heart syndrome, spina bifida and gastroschisis in newborns.
The study also noted that when opioids were used long-term during pregnancy, “there is a known risk for neonatal opioid dependence and subsequent withdrawal symptoms in the first few days of life.”
“Pain occurring at some time during the course of pregnancy is common,” said Edward A. Yaghmour, MD, chair of the American Society of Anesthesiologists’ Committee on Obstetric Anesthesia.
“We need to carefully balance medications given to the mother and the risk to her and her baby. For example, we would never stop giving anti-seizure medication or medication for diabetes; the danger in those situations is clear. With opioids, there are simply not enough data to have a clear answer. Untreated severe pain in the mother may also be harmful to the fetus.”
Yaghmour says other treatments and therapies should be the first-line treatment before opioids.
Last month the American Society of Anesthesiologists urged its 52,000 members not to prescribe opioids as “first-line therapy” for any patient with chronic non-cancer pain.