Microcephaly: an epidemiologic analysis.

Objective: This study was conducted to identify all risk factors that are associated with microcephaly and to quantify the magnitude of risk that is associated with these factors.

Study Design: This population-based case-control study used the Missouri Birth Defects Registry to identify 360 microcephaly cases and 3600 control cases during 1993 through 1999. Logistic regression was used to calculate adjusted odds ratios and 95% CIs.