OBJECTIVE To investigate the effect of infusion of sodium bicarbonate in amniotic cavity and exchange of amniotic fluid for fetus with distress and acidosis. METHODS The patients included 40 cases of oligohydramnios with mild and serious abnormality of fetal heart rate and amniotic fluid contamination of degree II or more during the labor. The 40 cases had exchange of amniotic fluid with infusion under continuous monitoring. Twenty of them had infusion with 5% sodium bicarbonate into amniotic cavity; the other 20 cases received 5% sodium bicarbonate intravenous in fusion. After the labor all the patients had test of arterial blood gas in umbilical cord and the fetuses were evaluated with Apgar score. RESULTS (1) the effective rate was 88% in the group of infusion into amniotic cavity and 85% in the group of exchange of amniotic fluid. (2) The arterial blood pH, PO(2), HCO(3)(-), ABE, SBE in the group of amniotic cavity infusion with 5% sodium bicarbonate were all higher than group of IV infusion, however PCO(2) was significantly lower than the group of IV (P < 0.05). CONCLUSION Infusion into amniotic cavity and exchange of amniotic fluid is effective therapy for fetal distress due to oligohydramnios and can prevent meconium aspiration syndrome; infusion of antacids medicine (5% sodium bicarbonate) into amniotic cavity is effective and safe therapy for fetus with acidosis.