1986년 4월부터 1986년 9월까지 서울대학교병원 산부인과외래에 내원한 정상임부 43명, 분만을 위하여 보원에 입원한 임부중 질식분만한 임부 33명과 제왕절개술로 분만한 임부 21명 및 정상 비임부 21명을 대상으로 모체혈장 -Ep치를 방사면역법으로 측정하여 다음과 같은 결론을 얻었다. 1. 임신기간중 모체혈장 -Ep치는 치는 각 임신기수에서 유의한 변화를 하지 않았으며 정상 비임부의 것보다 약간 증가하였으나 유의한 차가 없었다. 2. 모체혈장 -Ep치는 분만 제 1기에서 임신 제 3기보다 유의하게 증가하였으며, 진통이 진행됨에 따라 점차 증가하여 분만 제 2기에 최고치에 도달한 후에 감소되어 분만 제 3기에서 분만 제 1기의 후기의 수준이 되었다. 3. 각 분만기수에서 자연분만과 oxytocin유도분만시의 모체혈장 -Ep치 사이에는 유의한 차가 없었다. 4. 분만방식에 따른 모체혈장 -Ep치는 응급제왕절개분만의 경우가 선택적 제왕절개분만의 경우보다 유의하게 높았으나 자연질식분만 및 흡인질식분만의 경우와는 유의한 차가 없었다.5. 응급제왕절개술과 선택적 제왕절개술의 경우 마취전과 마취후의 모체혈장 -Ep치는 각각 유의한 차가 없었다.

This study was undertaken to evaluate the changes in maternal plasma beta-endorphin level during pregnancy, labor, and delivery, and the effects of the mode of delivery and general anesthesia on maternal plasma -endorphin level. Immunoreactive -endorphin was measured by radioimmunoassay in venous plasma of 43 pregnant women during pregnancy, 33 pregnant women during labor, and 21 pregnant women submitted to emergency or elective cesarean section prior to induction and immediately after fetal extration. The venous plasma samples of 21 nonpregnant women were taken as control. The results were as follows: 1. The mean maternal plasma -endorphin level was not changed significantly during pregnancy and was slightly increased in pregnant women than in nonpregnant women. 2. The mean maternal plasma -endorphin level increased significantly during the first stage of labor than in the third trimester of pregnancy. As labor progressed, the mean maternal plasma -endorphin level increased furthermore, peakde at the second stage of labor, and thereafter declined to the level of the first stage of labor. 3. There were no significant differences in the mean maternal plasm -endorphin levles between spontaneous and oxytocin-induced labor and delivery. 4. The mean maternal plasma -endorphin level in emergency section group after fetal extraction was significantly higher than that in the elective section group, but there was no significant difference in the mean maternal plasma -endorphin level among the spontaneous delivery group, the vacuum extraction group and the cesarean section group. 5. No significant difference was found in the mean maternal plasma -endorphin levels of women underwent emergency or elective cesarean section prior to induction of anesthesia and immediately after fetal extraction.