Opioid substitution treatment (OST) for opiate dependent pregnant women for treatment and obstetrical outcomes

Evidence-based international guidelines (WHO, 2014) strongly recommend to advise opioid dependent pregnant women to start or continue substitution treatment with either methadone or buprenorphine.

Substitution treatment for pregnant women was found effective in 2 systematic review (EMCDDA 2014, Minozzi et al., 2020 - 3RCTS methadone vs buprenorphine, 1 RCT methadone vs slow-release morphine) in:

• reducing drop-out rates RR 0.66, 95 % CI 0.37 to 1.20, 3 studies, N=223 (no differences between OST medications)
• higher birth weight (may be higher in the buprenorphine group)
• reducing use during pregnancy (RR 1.81, 95 % CI 0.70 to 4.68, 2 studies, N=151)
• new-borns treated for neonatal abstinence syndrome RR 1.19, 95% CI 0.87 to1.63 (no differences between OST medications)

A systematic review with meta-analysis (Zedler et al, 2016, 3 RCTs, N= 223 and 15 observational studies, N=1 923), compared buprenorphine with methadone to treat pregnant women with opioid use disorder and found:

• lower risk of preterm birth (RR =0.40, 95 % CI = 0.18-0.91)
• greater birth weight (weighted mean difference (WMD) =277g, 95 % CI = 104-450)
• larger head circumference (WMD=0.90cm, 95 % CI=0.14-1.66)

A systematic review (Link et al., 2020, 5 RCTS, N= 1 875) found that substitution treatment with buprenorphine-naloxone have similar pregnancy outcomes when compared to women undergoing treatment with other forms of OST.

A more recent systematic review (Ordean & Tubman-Broeren, 2023, 5 studies) confirmed that using buprenorphine-naloxone during pregnancy lead to:

• reduced opioid use 
• similar gestation outcomes to those exposed to methadone, buprenorphine monotherapy, illicit opioids, or no opioids.