Weight Loss In Baby

My daughter had her check up today. She lost a few more ounces since her last appointment. She will be 3 weeks old Wednesday. She was 7 pounds 4 oz at birth. Weighed 6 pounds 13 oz at the hospital. First check up she was 6 pounds 14 oz. Today she's 6 pounds 11 oz. Has anyone had this to happen to their son or daughter?

Update: My husband figured out what happened as to why she was probably loosing weight. Our baby brezza formula machine need to be checked. Not the right amount of formula was coming out. She wasn't getting enough to eat.