Hirst J J, Haluska G J, Cook M J, Novy M J
Division of Reproductive Biology and Behavior, Oregon Regional Primate Research Center, Beaverton 97006.
Am J Obstet Gynecol. 1993 Aug;169(2 Pt 1):415-22. doi: 10.1016/0002-9378(93)90099-5.
The purpose of the study was to determine whether rising maternal or fetal plasma oxytocin concentrations could be responsible for the increasing levels of nocturnal uterine activity on the nights preceding delivery.
Chronically catheterized pregnant rhesus monkeys were exposed to a 16-hour light, 8-hour dark photoperiod (dark 11 PM to 7 AM). Uterine activity and maternal arterial plasma oxytocin concentrations were measured concurrently at weekly intervals in late gestation, on the night preceding term delivery (158 to 167 days, n = 4), and during delivery (149 to 170 days, n = 6). Fetal carotid arterial plasma oxytocin levels were measured during episodes of nocturnal uterine activity in six animals. The effect of oxytocin infusions into the fetus (30 to 480 ng/kg/hr) on uterine activity and on maternal and fetal plasma oxytocin levels was also determined (n = 3).
Maximal nocturnal oxytocin concentrations in the maternal plasma rose progressively during late gestation from 9.9 +/- 3.5 pg/ml at 130 to 139 days to 28.7 +/- 9.8 pg/ml on the night preceding term delivery (p < 0.005); a significant increase in nocturnal uterine activity accompanied this rise (p < 0.001). Maternal oxytocin concentrations were elevated during labor and increased further at delivery (62.5 +/- 5.5 pg/ml, p < 0.05). There was no increase in fetal plasma oxytocin during nocturnal uterine activity (3.1 +/- 0.2 pg/ml) or during labor. Fetal oxytocin infusions raised fetal plasma oxytocin concentrations sixtyfold but had no effect on maternal plasma oxytocin concentrations or on uterine activity.
Elevated maternal plasma oxytocin concentrations are responsible, at least in part, for the increasing magnitude of nocturnal uterine activity episodes as term approaches and for the elevated uterine activity before delivery at night. Fetal plasma oxytocin does not contribute to nocturnal uterine activity or to maternal plasma oxytocin concentrations.
本研究旨在确定母体或胎儿血浆中催产素浓度升高是否可能导致分娩前夜间子宫活动水平增加。
对长期插管的怀孕恒河猴进行16小时光照、8小时黑暗的光周期处理（黑暗时间为晚上11点至早上7点）。在妊娠晚期、足月分娩前一晚（158至167天，n = 4）以及分娩期间（149至170天，n = 6），每周同时测量子宫活动和母体动脉血浆催产素浓度。在六只动物的夜间子宫活动期间测量胎儿颈动脉血浆催产素水平。还确定了向胎儿输注催产素（30至480 ng/kg/小时）对子宫活动以及母体和胎儿血浆催产素水平的影响（n = 3）。
母体血浆中夜间催产素最大浓度在妊娠晚期逐渐升高，从130至139天的9.9±3.5 pg/ml升至足月分娩前一晚的28.7±9.8 pg/ml（p < 0.005）；夜间子宫活动显著增加伴随这种升高（p < 0.001）。分娩时母体催产素浓度升高，并在分娩时进一步增加（62.5±5.5 pg/ml，p < 0.05）。夜间子宫活动期间（3.1±0.2 pg/ml）或分娩期间胎儿血浆催产素没有增加。向胎儿输注催产素使胎儿血浆催产素浓度升高60倍，但对母体血浆催产素浓度或子宫活动没有影响。
母体血浆催产素浓度升高至少部分导致接近足月时夜间子宫活动发作幅度增加以及夜间分娩前子宫活动增强。胎儿血浆催产素对夜间子宫活动或母体血浆催产素浓度没有影响。
