Does having a normal but lower BMI effect fertility?

My trainer said that I am .01 from being having a body composition that is considered underweight. Which means I have a very low body fat percentage. I am fit, and eat clean. My husband, and I have been ttc for almost 3 years now. We’ve seen infertility doctors, and have had <a href="https://glowing.com/glow-fertility-program">IUI</a>’s. The cause is unknown. Could my BMI effect it?