Growth retardation after dexamethasone administration: assessment by knemometry.

Knemometry has been used to measure lower leg growth during 32 nine day courses of dexamethasone in 26 babies ranging from 24 to 32 weeks' gestation at birth. Mean leg length velocity was 0.37 mm/day in the 10 days before steroids. Administration of dexamethasone was associated with a decrease in velocity in all babies, and in 15 leg shortening was documented. Mean leg length velocity during steroid treatment was -0.003 mm/day. After the course of dexamethasone was completed there was an immediate increase in leg length velocity to a mean of 0.52 mm/day over the first 10 days then falling to a value similar to the growth velocity observed before treatment. Leg length had reached the value predicted by growth before steroids about 30 days after dexamethasone. The reduction in leg length velocity occurred despite a significant increase in energy intake and decrease in oxygen requirements.