Matsuda Y, Patrick J, Carmichael L, Challis J, Richardson B
Department of Obstetrics and Gynaecology, Kagoshima Medical School, Japan.
Am J Obstet Gynecol. 1992 Aug;167(2):531-40. doi: 10.1016/s0002-9378(11)91449-5.
The purpose of our study was to examine the effects of induced hypoxia on endocrine, cardiovascular, and biophysical measurements of the ovine fetus at 0.6 (83 to 93 days) of gestation and to compare the fetal responses at this earlier gestation with those reported near term.
Fourteen fetal sheep were studied (9 in the hypoxia group and 5 in the control group) at 0.6 of gestation during a 24-hour control period, 8 hours of either sustained hypoxemia or room air, and a 40-hour recovery period.
Induced fetal hypoxemia resulted in a progressive lactic metabolic acidosis; however, all fetuses had recovered within 24 hours. The fetal endocrine response was variable with norepinephrine, the only measured hormone showing a significant hypoxia-related increase (p less than 0.05). Fetal heart rate and mean arterial blood pressure showed little hypoxia-induced change, although fetal heart rate was significantly increased over the first 2 hours (p less than 0.05). The percent time fetal breathing movements, electroocular activity, and nuchal muscle activity likewise showed little hypoxia-induced change.
The cardiovascular and biophysical response of the preterm fetus to induced hypoxemia is thus much less pronounced than that of the older gestational-aged fetus; this difference may impact on survival and the success of antenatal assessment protocols.
我们研究的目的是检查在妊娠0.6（83至93天）时诱导性低氧对绵羊胎儿内分泌、心血管及生物物理指标的影响，并将妊娠早期胎儿的反应与足月时报告的反应进行比较。
在妊娠0.6时，对14只胎羊进行研究（低氧组9只，对照组5只），包括24小时的对照期、8小时的持续性低氧血症或室内空气环境期以及40小时的恢复期。
诱导性胎儿低氧血症导致进行性乳酸代谢性酸中毒；然而，所有胎儿在24小时内均恢复。胎儿内分泌反应存在差异，去甲肾上腺素是唯一检测到的与低氧相关显著增加的激素（p<0.05）。胎儿心率和平均动脉血压在低氧诱导下变化不大，尽管在最初2小时内胎儿心率显著增加（p<0.05）。胎儿呼吸运动、眼电活动和颈部肌肉活动的时间百分比同样在低氧诱导下变化不大。
因此，早产胎儿对诱导性低氧血症的心血管和生物物理反应远不如孕龄较大的胎儿明显；这种差异可能影响生存及产前评估方案的成功率。
