Managing Opioid Dependence in Pregnancy

Women with opioid dependence who become pregnant are at risk for adverse pregnancy outcomes and perinatal complications. When doses of opioids are tapered during pregnancy, the result is often relapse to former use. When opioids are discontinued abruptly in opioid-dependent pregnant women, preterm labor, fetal distress, or fetal death can occur.

Opioid agonist maintenance treatment with a long-acting synthetic opioid, such as methadone or buprenorphine, is the standard of care for pregnant women with opioid dependence.^1-3 Methadone must be prescribed by and dispensed on a daily basis by a registered substance abuse treatment program. Buprenorphine, however, can be prescribed by a specially credentialed office-based physician.

The advantages of buprenorphine over methadone are a lower risk of overdose, fewer drug interactions, the option for outpatient treatment without the need for daily visits to a licensed treatment program, and evidence of less severe neonatal abstinence syndrome (NAS).¹ The disadvantages of buprenorphine, when compared with methadone, are possible hepatic dysfunction, lack of long-term data on infant and child effects, a clinically important patient dropout rate because of dissatisfaction with the drug, a more difficult induction with the potential risk of precipitated withdrawal, and an increased risk of diversion of prescribed buprenorphine.

In a trial comparing the neonatal effects of buprenorphine and methadone, the buprenorphine-exposed neonates required an average of 89% less morphine to treat NAS, had a 43% shorter hospital stay, and had a 58% shorter duration of medical treatment for NAS.⁴ If methadone is being used, transitioning to buprenorphine is not advised because of the significant risk of precipitated withdrawal.

Both the dose and the duration of treatment play an important role in pregnancy outcomes. Most women will require a dose adjustment usually at the beginning of the third trimester as a result of changes in metabolic rates, increased estrogen levels, and enzyme induction.² When maintenance treatment is given throughout the entire pregnancy, birth weights were higher and mothers were more likely to abstain from concomitant medication misuse.⁵

Breastfeeding should be encouraged in women without HIV infection who have no other contraindications. Despite the current buprenorphine package insert advising against breastfeeding, a consensus panel believes that the effects on the infant are likely to be minimal and that breastfeeding is not contraindicated.^1,6

Pertinent Points:

Early and closely monitored treatment using a multidisciplinary approach that includes social workers, nurses, psychologists, psychiatrists, obstetricians and gynecologists, anesthesiologists, neonatologists, and pediatricians optimizes pregnancy outcomes.

The choice of methadone or buprenorphine should be made on a patient-by-patient basis, with consideration of the patient’s history of opioid use, previous and current treatment experiences, medical circumstances, and treatment preferences.

Patient-stabilization with opioid-assisted therapy is compatible with breastfeeding.

References:

References
1. Committee opinion no. 524: opioid abuse, dependence, and addiction in pregnancy. Obstet Gynecol. 2012;119:1070-1076.
2. Unger A, Metz V, Fischer G. Opioid dependent and pregnant: what are the best options for mothers and neonates? Obstet Gynecol Int. 2012;2012:195954. Epub 2012 Feb 7.
3. Jones HE, Finnegan LP, Kaltenbach K. Methadone and buprenorphine for the treatment of opioid dependence in pregnancy. Drugs. 2012;72:747-757.
4. Jones HE, Kaltenbach K, Heil SH, et al. Neonatal abstinence syndrome after methadone or buprenorphine exposure. N Engl J Med. 2010;363:2320-2331.