Screening for postpartum depression at well child visits: evaluating the impact of Michigan's statewide initiative.

Objective: To examine a 2018 rule change allowing pediatric providers to bill the child's Medicaid ID for post-partum depression (PPD) screening of mothers conducted during well-child visits, and document its relationship with PPD treatment and infant hospitalizations.

Study setting and design: Screening rates during well-child visits are calculated at the zip code level and used in linear probability and Instrumental Variable (IV) models to examine increases in screening after the policy change and relate them to PPD treatment and infant hospitalizations.

Data sources and analytic sample: Individual-level Medicaid claims were used to compute PPD screening rates and measures of PPD treatment and infant hospitalization.

Principal findings: The policy was associated with increases in screening rates, although take up was uneven and overall screening rates remained low at 8.8%. There was little overall increase in treatment, although in zip codes in the top third of screening rates, higher screening was associated with 10.1% higher probability of maternal treatment. Zip codes with high fractions in poverty and/or minority had low screening rates, but screening was more likely to be associated with increases in treatment in these areas. There are no effects in the full sample of children, but among children above the poverty line, the observed increases in screening reduced the probability of infant hospitalization in the first six months by 7.7%.

Conclusions: The policy change had only limited success increasing screening, but increased screening could lead to more maternal PPD treatment and lower infant hospitalization rates if accompanied by expanded access to PPD treatment.