Do Medicaid family planning waivers reduce low birth weight prevalence? A nationwide, state-level analysis (.pdf)
Explanatory Variable (Policy intervention)
Medicaid section 1115 family planning waiver
Response Variable (Policy effect)
Percent of total live births with infant weight less than 2,500 grams
- U.S. Natality files
- Current Population Survey (CPS)
- Centers for Medicare and Medicaid Services (CMS)
- Guttmacher Institute
- Panel data set with 51 panels (50 states and the District of Columbia) over 21 years (1990 - 2010)
- Multivariate linear regression models with state and year fixed-effects, and correction for panel clustering
- Specificity and falsification analyses
Findings produced by this study failed to support the research hypothesis, that Medicaid family planning waivers are effective in lowering the prevalence of infants that weigh 2,500 grams or less at birth, when measured as a percentage of total live births per state, per year. Analyses consistently produced OLS coefficients on the policy intervention variable that were statistically insignificant and substantively small except for non-Hispanic Black populations. Estimated effects observed for this sub-group were associated with statistically significant, slightly higher low birth weigh rates compared with non-waiver states (0.007 percentage points; p < .05), an unanticipated outcome. See Table 25, OLS regression estimates for Medicaid family planning waiver effects (.pdf).
Too many infants in the United States are delivered with unhealthy weights. Low birth weight is a noteworthy public health problem because it is a major risk factor for infant mortality, it consumes a disproportionately high level of health care resources, and its prevalence continues to rise, despite investment of public resources aimed toward improving birth outcomes. One solution has been to foster adequate maternal health by preventing unintended pregnancy and promoting optimal birth spacing. Federal and state governments have responded to the need for managing the timing of conception with public policies designed to assure access to family planning services, particularly for low income residents who might not otherwise be able to afford them. Some states have relied on the Medicaid program to implement such policies, using Section 1115 family planning waivers to finance and deliver contraceptive medical care to populations who would not ordinarily be eligible for basic program enrollment.
A policy question relevant to infant health at birth is whether states using Medicaid family planning waivers exhibit improved birth weight outcomes as a result. This study evaluated the extent to which low birth weight prevalence varied in response to having a waiver policy in effect, while controlling for inter-state differences in maternal population according to demographic composition, labor force factors, and other non-medical determinants of health. Public use data from the U.S. Natality files, Current Population Survey (CPS), Centers for Medicare and Medicaid Services (CMS), and Guttmacher Institute were used to construct a panel data set with 51 panels (50 states and the District of Columbia) over 21 years (1990 – 2010).
Multivariate linear regression models including state and year fixed-effects, and correction for panel clustering, consistently produced ordinary least squares (OLS) coefficients on the policy intervention variable that were statistically insignificant and substantively small for all studied populations except non-Hispanic Black. Estimated effects observed for this sub-group suggested that states with waiver policies were associated with statistically significant, slightly higher low birth weigh rates compared with non-waiver states (0.007 percentage points; p < .05), an unanticipated outcome.
In interpreting these results, it is important to note several key points related to how the outcome variable was measured. Low birth weight prevalence was defined as percent of total live births with infant weight less than 2,500 g. Absolute number of low birth weight infants was not measured in response to policy intervention. Nor was the number of infants that weighed 2,500 g or more. Given that average U.S. birth rates were declining over the same period of time, it seems plausible that those declines may have occurred at all points along the continuum of the entire birth weight distribution rather than being limited to the low birth weight segment of the curve. If so, such a pattern would result in no observed change in the proportion of unhealthy weight newborns relative to total births. Similar measurement artifacts may also explain why low birth weight rates for non-Hispanic black populations were comparatively higher on average, for observations in which waivers were in effect. It seems unlikely that absolute low birth weight prevalence increased as a result of implementing waiver policies. A more plausible explanation is that the number of infants born at low birth weights did not change, while the number of infants born at healthy weights simultaneously declined, causing an increase in relative proportion of unhealthy weight infants to total births. If such a pattern were confirmed, it suggests the possibility that non-Hispanic Black populations exhibit different utilization patterns for family planning services, provided through the Medicaid program, compared with other populations studied. In summary, results from this study suggest that although waiver policies appear to be effective in reducing overall birth rates, there is no evidence to suggest that they are a useful approach for reducing low birth weight rates by mitigating underlying causes of low birth weight.