Congenital microcephaly hospitalizations in California infants: 1999-2013.

EHR collected data could be used as a complementary approach to track epidemiologic changes in microcephaly IRs. However, standardization in the use of microcephaly discharge diagnosis code and harmonization in the types of additional comorbidities to be excluded across analyses is mandatory to allow for prompt identification of true changes in microcephaly rates over time.