Bilhah (בִּלְהָה) is the Hebrew name of Rachel's handmaid in the Book of Genesis.
Bilhah is widely used in religious Jewish families.
Bilhah 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 Bilhah reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.