Maintenance agonist treatments for opiate dependent pregnant women

Minozzi S, Amato L, Vecchi S, Davoli M

Summary

Some women continue to use opiates when they are pregnant. Yet heroin readily crosses the placenta. Opiate dependent women experience a six-fold increase in maternal obstetric complications and give birth to low-weight babies. The newborn may experience narcotic withdrawal (neonatal abstinence syndrome), have development problems, increased neonatal mortality and a 74-fold increased risk of sudden infant death syndrome. Maintenance treatment with methadone provides a steady concentration of opiate in the pregnant woman's blood and so prevents the adverse effects on the fetus of repeated withdrawals. Buprenorphine is also used. They reduce illicit drug use, improve compliance with obstetric care and improve birth weight but are still associated with neonatal abstinence syndrome. The present review found few differences in newborn or maternal outcomes for pregnant opiate-addicted women who were maintained on methadone, buprenorphine or oral slow morphine from a mean gestational age of 23 weeks to delivery. Only three randomised controlled trials satisfied the criteria for the review, two from Austria (outpatients) and one from the USA (inpatients). The trials continued for 15 to 18 weeks. Two compared methadone with buprenorphine (48 participants) and one compared methadone with oral slow morphine (48 participants). The number of women who dropped out from treatment and the use of primary substance appeared to be the same for methadone and buprenorphine. Oral slow morphine seemed superior to methadone for the number of women who used heroin in their third trimester but without a clear improvement in infant birth weight or duration of neonatal abstinence syndrome.

The number of participants in the trials was very small and may not be sufficient to detect differences. Only one study reported on the number of cigarettes the women smoked, a mean of 29 cigarettes per day at enrolment and 14 cigarettes per day at delivery. All the included studies ended immediately after the baby was born. No severe complications were noted.