RELATIONSHIP BETWEEN PLASMA ADENOSINE CONCENTRATION AND BREATHING MOVEMENTS IN GROWTH-RETARDED FETUSES

OBJECTIVE: The purpose of this study was to investigate the relationsh ip between plasma adenosine concentration and breathing movements in g rowth-retarded fetuses. STUDY DESIGN: We measured the incidence of fet al breathing movements and breathing rate immediately before cordocent esis in 26 growth-retarded fetuses at 31 to 38 weeks' gestation. Blood retrieved by cordocentesis was then analyzed for umbilical venous pla sma adenosine concentration, blood gases, and pH. RESULTS: In growth-r etarded fetuses with hypoxia and acidosis plasma adenosine concentrati on was elevated and the incidence of fetal breathing movements was red uced. The change in plasma adenosine concentration correlated inversel y and significantly with the incidence of fetal breathing movements. C ONCLUSION: Decreased breathing movements correlate with elevated plasm a adenosine concentration in fetuses. We postulate that the enhanced a denosine formation in growth-retarded fetuses may modulate the inhibit ion of fetal breathing movements.