Head circumference at birth and exposure to tobacco, alcohol and illegal drugs during early pregnancy Juan A. Ortega-García & Jorge E. Gutierrez-Churango & Miguel F. Sánchez-Sauco & Miguel Martínez-Aroca & Juan L. Delgado-Marín & M. Sánchez-Solis & J. J. Parrilla-Paricio & Luz Claudio & Juan F. Martínez-Lage
