[Blood gas and acid-base equilibrium in normal pregnancy and pregnancy with fetal distress by vaginal delivery or cesarean section].

Blood gas and acid-base assessment of maternal dorsalis pedis artery and umbilical artery and vein was carried out immediately after delivery in 46 cases of normal term pregnancy and 41 cases of pregnancy with fetal distress (FD). Blood gas and acid-base equilibrium differences between vaginal delivery and cesarean section were studied. The results showed a low BE value (< -3mmol/L) in maternal artery of both groups, and that the other parameters were all within normal range, not being different between the normal pregnancy and FD group. Blood gas assaying of umbilical veins of the 2 groups also showed no difference. In comparison with the normal pregnant group, the FD group yielded significantly decreased values of pH, PO2 and O2Sat in umbilical artery but significantly increased PCO2 (P < 0.05). Women of both groups delivered vaginally had milder metabolic acidosis and slighter hypoxia than those delivered by cesarean section. Marked fetal acidosis and low Apgar score were more commonly seen in the FD group. These indicated that to delay labor to near term and to perform cesarean section for relieving fetal distress is advisable.