Maintenance agonist treatments for opiate-dependent pregnant women

Abstract

Background: The prevalence of opiate use among pregnant women can range from 1% to 2% to as high as 21%. Just in the United States alone, among pregnant women with hospital delivery, a fourfold increase in opioid use is reported from 1999 to 2014 (Haight 2018). Heroin crosses the placenta, and pregnant, opiate-dependent women experience a six-fold increase in maternal obstetric complications such as low birth weight, toxaemia, third trimester bleeding, malpresentation, puerperal morbidity, fetal distress and meconium aspiration. Neonatal complications include narcotic withdrawal, postnatal growth deficiency, microcephaly, neuro-behavioural problems, increased neonatal mortality and a 74-fold increase in sudden infant death syndrome. This is an updated version of the original Cochrane Review first published in 2008 and last updated in 2013.

Objectives: To assess the effectiveness of any maintenance treatment alone or in combination with a psychosocial intervention compared to no intervention, other pharmacological intervention or psychosocial interventions alone for child health status, neonatal mortality, retaining pregnant women in treatment, and reducing the use of substances.

Search methods: We updated our searches of the following databases to February 2020: the Cochrane Drugs and Alcohol Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and Web of Science. We also searched two trials registers and checked the reference lists of included studies for further references to relevant randomised controlled trials (RCTs).

Selection criteria: Randomised controlled trials which assessed the efficacy of any pharmacological maintenance treatment for opiate-dependent pregnant women.

Data collection and analysis: We used the standard methodological procedures expected by Cochrane.

Main results: We found four trials with 271 pregnant women. Three compared methadone with buprenorphine and one methadone with oral slow-release morphine. Three out of four studies had adequate allocation concealment and were double-blind. The major flaw in the included studies was attrition bias: three out of four had a high dropout rate (30% to 40%), and this was unbalanced between groups. Methadone versus buprenorphine: There was probably no evidence of a difference in the dropout rate from treatment (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.37 to 1.20, three studies, 223 participants, moderate-quality evidence). There may be no evidence of a difference in the use of primary substances between methadone and buprenorphine (RR 1.81, 95% CI 0.70 to 4.68, two studies, 151 participants, low-quality evidence). Birth weight may be higher in the buprenorphine group in the two trials that reported data MD;-530.00 g, 95%CI -662.78 to -397.22 (one study, 19 particpants) and MD: -215.00 g, 95%CI -238.93 to -191.07 (one study, 131 participants) although the results could not be pooled due to very high heterogeneity (very low-quality of evidence). The third study reported that there was no evidence of a difference. We found there may be no evidence of a difference in the APGAR score (MD: 0.00, 95% CI -0.03 to 0.03, two studies,163 participants, low-quality evidence). Many measures were used in the studies to assess neonatal abstinence syndrome. The number of newborns treated for neonatal abstinence syndrome, which is the most critical outcome, may not differ between groups (RR 1.19, 95% CI 0.87 to1.63, three studies, 166 participants, low-quality evidence). Only one study which compared methadone with buprenorphine reported side effects. We found there may be no evidence of a difference in the number of mothers with serious adverse events (AEs) (RR 1.69, 95% CI 0.75 to 3.83, 175 participants, low-quality evidence) and we found there may be no difference in the numbers of newborns with serious AEs (RR 4.77, 95% CI 0.59, 38.49,131 participants, low-quality evidence). Methadone versus slow-release morphine: There were no dropouts in either treatment group. Oral slow-release morphine may be superior to methadone for abstinence from heroin use during pregnancy (RR 2.40, 95% CI 1.00 to 5.77, one study, 48 participants, low-quality evidence). In the comparison between methadone and slow-release morphine, no side effects were reported for the mother. In contrast, one child in the methadone group had central apnoea, and one child in the morphine group had obstructive apnoea (low-quality evidence).

Authors' conclusions: Methadone and buprenorphine may be similar in efficacy and safety for the treatment of opioid-dependent pregnant women and their babies. There is not enough evidence to make conclusions for the comparison between methadone and slow-release morphine. Overall, the body of evidence is too small to make firm conclusions about the equivalence of the treatments compared. There is still a need for randomised controlled trials of adequate sample size comparing different maintenance treatments.