OBJECTIVE:

Prior studies noted elevated preterm birth (PTB) rates among opiate-addicted women treated with methadone. We sought to determine the risk factors for PTB in this population.

STUDY DESIGN:

We performed a retrospective cohort study of opiate-addicted gravid women treated with methadone who delivered a single neonate between 2000 and 2006. Variables evaluated as potential risk factors for PTB less than 37 weeks included medical and infectious comorbidities and "supplements to methadone" (illicit drugs and/or alcohol).

RESULTS:

The overall PTB rate was 29.1% (75/258). No medical or infectious comorbidity was predictive of PTB. Among women abusing 0, 1, 2, or 3 or more supplements in addition to methadone, the PTB rate was 24.2% (reference), 25.5% (P = .50), 47.6% (P = .04), and 64.7% (P = .01), respectively.

CONCLUSION:

The PTB rate among women on methadone (29.1%) is nearly 3 times the national average (11.1%), and those abusing 2 or more supplements to methadone are at further increased risk for PTB.