FETAL AND MATERNAL TRANSCUTANEOUS PCO2 LEVELS DURING LABOR AND THE INFLUENCE OF EPIDURAL ANALGESIA

The Departments of Obstetrics and Gynaecology of the Hvidovre Universi ty of Copenhagen and the Free University of Amsterdam collaborated in a study on the relationship of maternal and fetal acid-base state in t he intrapartum period. Transcutaneous PCO2 levels of mother (tcPCO(2)m ) and fetus (tcPCO(2)f) were continuously recorded in 52 patients duri ng labour, TcPCO(2)f and tcPCO(2)m correlated significantly (r = 0.42, P < 0.002), During the first stage of labour, a rather stable level w as found for tcPCO(2)f (7.7 +/- 1.6 kPa) and tcPCO(2)m (4.4 +/- 0.8 kP a). TcPCO(2)m decreased significantly to 3.8 +/- 0.7 kPa (P < 0.01) in the hour before full cervical dilatation, probably due to maternal hy perventilation as a reaction to painful uterine contractions, TcPCO(2) f likewise showed a tendency to a decrease to a mean value of 7.4 +/- 1.5 kPa, In eight cases epidural analgesia was applied because of pain ful uterine contractions. Prior to the epidural analgesia, tcPCO(2)m ( 3.8 +/- 0.8 kPa) and tcPCO(2)f (6.7 +/- 1.7 KPa) were significantly lo wer in this subgroup compared to the total population, After pain reli ef by application of epidural analgesia, tcPCO(2)m and tcPCO(2)f retur ned to the population mean.