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.

RESULTS

Significant risk factors for isolated microcephaly include alcohol use, inadequate weight gain during pregnancy, inadequate prenatal care, black race, and low education. Mothers with one previous live birth were protected against isolated microcephaly compared with nulliparous women.

CONCLUSION

Our results suggest that microcephaly may arise from some preventable factors. These findings may be useful in aiding clinicians, patients, and policymakers in reducing the risk of microcephaly, a source of high perinatal mortality and morbidity rates.