Use of TRH in the fetus to advance lung maturity.

Maturation of the fetal lung is a complex process involving interactions between intrinsic biologic development of several cell types and hormonal triggering of biochemical and functional alterations. Catecholamines, corticosteroids, thyroid hormones and perhaps prolactin, all influence the transition from non-functional to functional pulmonary tissue, the most critical component necessary for extrauterine existence. The assimilation of clinical observation, in vitro experimentation, and animal studies has led to the potential of therapeutic intervention in a manner with minimal hazard to the fetus. The use of maternally administered TRH to reduce the incidence and severity of RDS, although still in the early stages of clinical application, appears to justify the long years of careful research in this area.