“…While many SUD treatment barriers for pregnant women have been described 8,9 and a prior study has examined treatment receipt among women with SUD and OUD in the 24 months surrounding delivery, 10 little is known about rates of SUD treatment for women in dyads affected by substance use in the immediate postpartum period (i.e., the start of the so-called fourth trimester) 11 or the sociodemographic and clinical characteristics associated with treatment receipt. Therefore, using an innovative but infrequently used approach of linking mother-infant dyads in Medicaid data, 10,12 we sought to (1) identify sociodemographic, health insurance, utilization, and clinical characteristics of mothers of infants with NAS and PSE who did or did not receive SUD treatment in the first 60 days postpartum, and (2) for those receiving treatment, describe the timing of postpartum treatment receipt. Building on literature describing factors associated with prenatal SUD treatment receipt, 13,14 we hypothesized that most mothers in substance-affected dyads would not receive timely postpartum treatment for SUD, and that race, urbanicity, duration of Medicaid enrollment, prenatal care attendance, and co-occurring mental health conditions would be associated with receipt of SUD treatment in the 60 days after delivery.…”