A Small Risk of Increased Congenital Abnormalities from Opioids in Pregnancy

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In a new study in the Canadian Medical Association Journal, researchers drawing on a provincial database report a small increased risk of congenital abnormalities in infants exposed to opioid medications in the first trimester of pregnancy.

Prescribed opioid pain medications are capable of crossing the placenta and have the potential to cause harm. In a study comparing placental crossing rates for various opioids, oxycodone, a commonly prescribed opioid for pain relief, was the fastest. About 2%–4% of foetuses are exposed to these drugs. To determine the association between opioid pain medications in early pregnancy and congenital abnormalities in infants, investigators analysed administrative health data from Ontario on almost 600 000 birth parent–infant pairs. 

Among the infants included in the study, 2% (11 903) were exposed in utero to opioid analgesics, such as codeine, oxycodone, hydromorphone, tramadol, and morphine. Analysis showed a small increased risk of major anomalies with exposure to tramadol and morphine, and of minor anomalies with exposure to codeine, hydromorphone and oxycodone. Specific congenital anomalies observed included gastrointestinal and genital anomalies, neoplasms and tumours, and ankyloglossia.

This study adds to the evidence from previous studies in Sweden and Norway and also from a recent study of pregnant US Medicaid beneficiaries that suggested a small increased risk of congenital anomalies, an important finding for a pregnant person who may be prescribed opioids for pain relief.

“Both the potential for harm or distress to the pregnant person as a consequence of foregoing treatment and the subsequent risk to the infant must be considered for effective treatment,” the authors concluded. “These findings further quantify harms associated with prenatal exposure to opioid analgesics to inform treatment choices for pain in pregnancy.”

Source: EurekAlert!