Delivering equity: preterm birth by socioeconomic class before and after coverage of 17-hydroxyprogesterone caproate

We compare the preterm birth rate across socioeconomic strata in Michigan before and after the decision by Michigan Medicaid to provide coverage for 17-hydroxyprogesterone caproate (17-OHP), a costly medication for recurrent preterm birth prevention. We retrospectively analyzed births recorded in the Michigan Department of Health &amp; Human Services database from 2008-2016, comparing the rate of preterm birth stratified by standardized US Census Bureau socioeconomic levels (affluent, higher-middle class, lower-middle class, and poverty) across three time periods: pre-Federal Drug Administration approval of 17-OHP (2008–2011), pre-Medicaid coverage (2012–2014), and post-Medicaid coverage (2015–2016). Of 1,034,901 total live births, 10% (<i>N</i> = 103,869) were premature. An ANOVA with post-hoc testing showed the preterm birth rate was highest for those living in poverty, lower for the lower-middle class, and lowest for the collective higher-middle and affluent classes. The preterm birth rate dropped for all classes after Michigan Medicaid began paying for 17-OHP, but inter-class gaps remained. Extended financial coverage for 17-OHP may have contributed to modest decreases in preterm birth rates, but this policy did not equalize outcomes between those with disparate resources.