Cynthia is a moderately popular girls' name in United States, ranking #145 in 1999 with 2,225 recorded births. The name reached its all-time peak in 1996 with 3,189 births ranking #101. Since 1996, the popularity has decreased by 30.2%. In 1999, approximately 1 in every 797 girls born was named Cynthia. FALLING Recent data shows the name is currently falling.