Risk factors for congenital microcephaly in the pre-Zika era.

Risk factors differed for isolated and non-isolated microcephaly. While some findings support previously reported associations, (e.g., smoking, alcohol, underweight BMI), we also identified risk factors not previously described, notably NSAID use for isolated microcephaly and urinary tract infection for non-isolated microcephaly; however, these results should be viewed as hypothesis generating.