Opioid Analgesic Use During Pregnancy: Commentary by Sait Ashina, MD

Opioids are among the most potent and important analgesics used for the treatment of acute and chronic pain. The use of opioids in the treatment of headache has been limited. One of the major reasons for this is the availability of conventional therapies for migraine, such as migraine-specific abortive medications and effective preventive medications. Moreover, there are concerns about overuse and possible side effects regarding opioid use in patients with headache. Opioids also have been shown to increase the risk for medication overuse headache in persons with migraine in epidemiologic and clinic-based observational studies.

In a limited group of headache patients, however, opioids can result in headache reduction and functional improvement for the first time in their lives. These are usually patients who do not have risk factors for substance abuse, a previous history of substance abuse, substance abuse in the family, a history of physical or emotional abuse, limited stress management skills, a previous criminal history, treatment in other pain centers, or major psychiatric comorbidities and patients refractory to conventional treatments. Multiple tools, scales, and questionnaires have been developed to help physicians predict the risk of abusive behaviors in patients. Physicians who are planning or prescribing opioids must use these tools.

Intractable primary headache, such as migraine during pregnancy, is a challenging clinical scenario for the patient and the physician. Pharmacologic treatment options for migraine have been limited to acetaminophen and antinauseants for abortive therapy and propranolol for preventive therapy. Due to the safety profile and limited evidence, physicians are less likely to prescribe other conventional treatments for migraineurs during pregnancy. Opioids are occasionally used for severe and intractable migraine pain.

Moreover, women with chronic pain of various etiologies may experience aggravation of pain during the pregnancy. One example is the worsening of back pain in patients with chronic musculoskeletal pain, which may necessitate the use of opioids to relieve the intractable pain.

The recent case-control epidemiologic study by Broussard and colleagues demonstrated the association between the use of opioids in early pregnancy and the risk of birth defects. A stronger association between opioid use and birth defects was found during early pregnancy.

This study raises major concerns about the use of opioids during early pregnancy; however, the study also has several limitations. This is a case-controlled study with exposure information obtained by maternal self-report. In addition, medication doses were not reported, and therefore a dose-response relationship could not be assessed.