Insurance coverage affects health care access for many delivering women diagnosed with perinatal mood and anxiety disorders (PMADs). The Mental Health Parity and Addiction Equity Act (MHPAEA; passed in 2008) and the Patient Protection and Affordable Care Act (ACA; passed in 2010) aimed to improve health care access. To assess associations between MHPAEA and ACA implementation and psychotherapy use and costs among delivering women overall and with PMADs. This cross-sectional study conducted interrupted time series analyses of private insurance data from January 1, 2007, to December 31, 2019, for delivering women aged 15 to 44 years, including those with PMADs, to assess changes in psychotherapy visits in the year before and the year after delivery. It estimated changes in any psychotherapy use and per-visit out-of-pocket costs (OOPCs) for psychotherapy associated with MHPAEA (January 2010) and ACA (January 2014) implementation. Data analyses were performed from August 2022 to May 2023. Implementation of the MHPAEA and ACA. Any psychotherapy use and per-visit OOPCs for psychotherapy standardized to 2019 dollars. The study included 837 316 overall deliveries among 716 052 women (mean [SD] age, 31.2 [5.4] years; 7.6% Asian, 8.8% Black, 12.8% Hispanic, 64.1% White, and 6.7% unknown race and ethnicity). In the overall cohort, a nonsignificant step change was found in the delivering women who received psychotherapy after MHPAEA implementation of 0.09% (95% CI, -0.04% to 0.21%; P = .16) and a nonsignificant slope change of delivering women who received psychotherapy of 0.00% per month (95% CI, -0.02% to 0.01%; P = .69). A nonsignificant step change was found in delivering individuals who received psychotherapy after ACA implementation of 0.11% (95% CI, -0.01% to 0.22%; P = .07) and a significantly increased slope change of delivering individuals who received psychotherapy of 0.03% per month (95% CI, 0.00% to 0.05%; P = .02). Among those with PMADs, the MHPAEA was associated with an immediate increase (0.72%; 95% CI, 0.26% to 1.18%; P = .002) then sustained decrease (-0.05%; -0.09% to -0.02%; P = .001) in psychotherapy receipt; the ACA was associated with immediate (0.77%; 95% CI, 0.26% to 1.27%; P = .003) and sustained (0.07%; 95% CI, 0.02% to 0.12%; P = .005) monthly increases. In both populations, per-visit monthly psychotherapy OOPCs decreased (-$0.15; 95% CI, -$0.24 to -$0.07; P < .001 for overall and -$0.22; -$0.32 to -$0.12; P < .001 for the PMAD population) after MHPAEA passage with an immediate increase ($3.14 [95% CI, $1.56-$4.73]; P < .001 and $2.54 [95% CI, $0.54-$4.54]; P = .01) and steady monthly increase ($0.07 [95% CI, $0.02-$0.12]; P = .006 and $0.10 [95% CI, $0.03-$0.17]; P = .004) after ACA passage. This study found complementary and complex associations between passage of the MHPAEA and ACA and access to psychotherapy among delivering individuals. These findings indicate the value of continuing efforts to improve access to mental health treatment for this population.