In considering advances of the past year in obstetrics and gynecology, three areas of clinical significance have been selected. They are (1) the use of ritodrine hydrochloride in preterm labor, (2) the increasing recognition of<i>Chlamydia trachomatis</i>as a significant pathogen in the female reproductive organs, and (3) the use of fine-needle aspiration biopsy in lieu of the more traditional methods of tissue sampling. Of course, these events did not occur during just the past year, but they gained considerable attention during 1980. <h3>Ritodrine</h3> Prematurity is the leading cause of perinatal morbidity and mortality. It has been estimated that about 8% of liveborn infants in the United States weigh less than 2,500 g. Many cases are the result of "accidents" of pregnancy such as abruptio placentae, premature rupture of the membranes, and placenta previa. A large number, however, are caused by labor that begins prematurely without known cause. It is