Supporting women through opioid dependence treatment in pregnancy and after birth

Methadone and buprenorphine are the recommended treatments for opioid dependence during pregnancy and the postpartum period. Pregnancy and the first year postpartum mark the beginning of the first 2000 days of life, a critical period for physical, cognitive, social and emotional development. During this time, supporting opioid-dependent women to access and remain in treatment is essential to reduce the risk of adverse outcomes associated with opioid dependence. Engagement in treatment also facilitates ongoing contact with antenatal, postnatal, and broader health and social support services, improving outcomes for both women and their children.

In Australia, the methadone program for opioid dependence was established in the 1970s, and it has since been the standard treatment during pregnancy. The only Australian population-based study data examining treatment engagement during pregnancy was published in 2006 and reported that the number of women in New South Wales receiving methadone at the time of birth increased from 62 in 1992 to 459 in 2002.

Buprenorphine was introduced in 2001, and its use in Australia increased substantially from an estimated 1 871 clients in January 2013 to 28 000 in December 2022. Although buprenorphine was endorsed for use in pregnancy in the mid-2010s, a comprehensive understanding of treatment retention and pregnancy outcomes associated with buprenorphine compared with methadone is still lacking.

Despite these changes in clinical practice, contemporary Australian data on engagement in methadone and buprenorphine treatment during pregnancy and continuity of care after birth remain limited. Up-to-date evidence can inform workforce training, resource allocation and service delivery.

What we studied and our approach

The findings reported here are from three population-based studies (2004–2021, here, here, here) based on data from New South Wales on treatment during pregnancy, retention through childbirth and the first year after birth, and factors associated with treatment discontinuation.

We used routinely collected health data, including records of births, prescribing authorities for methadone and buprenorphine, hospital admissions, and contacts with health services. By linking these datasets, we were able to follow women across pregnancy and into the first year after birth, providing the most comprehensive pictures to date of engagement in opioid dependence treatment during the perinatal period in Australia.

What we found 

Among 5 212 women with a history of treated opioid dependence, three in four received treatment during pregnancy. Over time, there was a clear shift in medicine type. The proportion receiving methadone declined from 71% in 2005 to 37% in 2021, while buprenorphine use increased from 12% to 29%. This likely reflects evolving clinical guidance, increased availability of buprenorphine, and growing clinician confidence in its use during pregnancy.

Remaining engaged in treatment throughout pregnancy is critical, as discontinuing treatment can increase the risk of relapse to illicit opioid use and its associated harms. Encouragingly, our second study found that treatment retention during pregnancy was high. Among the 4472 women receiving treatment during pregnancy, 84% remained in treatment until childbirth.

While pregnancy often brings increased health care contact and support, the year after birth can be particularly challenging. Reduced health care contact, increased caregiving demands, and social and economic stressors may affect continuity of care. In our third study of 3393 women who were receiving treatment at the time of birth, nearly four in five (79%) continued treatment for a year after birth, providing reassuring evidence of sustained engagement.

In addition, we identified some groups of women who were more likely to discontinue treatment. Women who initiated treatment after becoming pregnant were less likely to remain engaged through to childbirth or in the first year post childbirth compared to women who were already in treatment at conception. This may reflect delayed access to care and the challenges of initiating and stabilising treatment during pregnancy.

Women receiving buprenorphine were also more likely to discontinue treatment than those receiving methadone. This is consistent with patterns seen in non-pregnant populations and may reflect differences in pharmacology, with buprenorphine as a partial agonist and methadone as a full agonist, as well as differences in clinical complexity and dosing adequacy. 

Women initiating treatment while in custody and those with co-occurring mental health conditions were also more likely to discontinue treatment. These findings highlight the intersecting clinical and social complexity experienced by many women with opioid dependence.

What this evidence means for practice and research

Taken together, these findings are encouraging. Most opioid-dependent women who gave birth received methadone or buprenorphine during pregnancy and remained engaged throughout pregnancy and the first postpartum year.

However, several groups may require additional support to maintain continuity of care, including women commencing treatment after conception, women in custody, women with co-occurring mental health conditions, and those receiving buprenorphine.

Beyond this new evidence, further research is needed to better understand the comparative effectiveness of methadone and buprenorphine in preventing adverse maternal and infant outcomes and whether such outcomes might be worse for buprenorphine given the higher risk of treatment discontinuation. Such evidence would help inform treatment decisions and service delivery during pregnancy and the postpartum period.

Note: The article includes terms that describe gender, including ‘women’ and ‘mothers’, the content should be considered inclusive of all pregnant people irrespective of whether they identify as women.

Dr Duong (Danielle) Tran is a Senior Research Fellow at the National Drug and Alcohol Research Centre at UNSW Sydney.

Dr Bianca Varney is a Postdoctoral Research Fellow at the National Drug and Alcohol Research Centre at UNSW Sydney.

Dr Alys Havard is an Associate Professor and Deputy Director of the National Drug and Alcohol Research Centre at UNSW Sydney

The authors have no competing interests to declare.