Christy is a diminutive of Christine / Christina — from the Greek christianos (follower of Christ). After her own postpartum hemorrhage in 2003, she founded Every Mother Counts in 2010 — dedicated to ending preventable maternal deaths; the organization has invested over $30 million in maternal health programs in 13 countries. Catherine Christy, Christy Mathewson is male (Hall of Fame pitcher).
Subject of countless 1990s fashion histories.
Christy does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Christy reduce to 3, The Communicator. This is a traditional interpretive system, not a factual claim about the name.