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Seizures are a common manifestation of neurologic dysfunction in neonates and carry a high risk for mortality and adverse long-term outcomes. U.S. birth certificates are a potentially valuable source for studying the epidemiology of neonatal seizures. However, the quality of the data is understudied.

We reviewed all U.S. birth records from 2003 to 2013 to describe the following: (1) rates of missing data, (2) evidence of underreporting, and (3) effect of the 2003 revision of the birth certificate form. We evaluated missingness by state, year, demographic, infant health, and medical care factors using bivariate analyses. To measure potential underreporting, we compared estimates to a published reference (0.95 per 1,000 term births). We developed criteria for data plausibility, and reported which states met these criteria.

Of 22,834,395 live term births (≥36 weeks of gestation) recorded using the revised form from 2005 to 2015, there were 5,875 with neonatal seizures, suggesting an incidence of 0.26 per 1,000 term births, one fourth of the expected incidence. Although the overall degree of missing seizure data was low (0.5%), missingness varied significantly by state, year, demographic, infant health, and medical care factors. After the 2003 birth certificate form revision, missing data and evidence of potential underreporting increased. Nine states met criteria for plausibility.

The value of U.S. birth certificate data for neonatal seizure epidemiology is limited by biased missingness, evidence suggestive of underreporting, and changes in reporting subsequent to the 2003 revision. There are plausible data from nine states, which merit investigation for further research.