What would cause person to grow 2-3 inches taller @ 39? no ht. change for 18-20 yrs before that. no other changes-hands, feet, face havent enlarged.

Nothing natural: A person can grow taller if she has not finished growing. A person cannot grow taller if she has already finished growing. Height growth finishes during the late teen years, or occasionally to age 21 or 22. There are internet stories of people growing taller at older ages, but those are science fiction stories... may be fun reading, but that's it.

Fake measurements: You don't grow taller at 39. If you had spinal surgery that corrected a bad scoliosis you might gain some height lost to the disease, but there is no condition that results in true growth.