Ogata E S, Kitterman J A, Kleinberg F, Dong L, Willis M, Mates J, Phibbs R H
Am J Obstet Gynecol. 1977 May 15;128(2):197-200. doi: 10.1016/0002-9378(77)90687-1.
We measured the residual placental blood volume (RPBV) of 20 infants delivered at term by cesarean section of women not in labor. In all cases, the umbilical cord was clamped within 40 seconds of birth. RPBV decreased significantly with increasing age at cord clamping. In addition, RPBV for infants with cords clamped within 20 seconds of birth correlated inversely with maternal systolic blood pressure (mean RPBV = 54.8 ml. per kilogram at 105 torr and 28.4 ml. per kilogram at 148 torr). However, RPBV did not correlate with maternal blood pressure for the whole group of 20 infants or for those with cords clamped later than 20 seconds after birth. These data indicated that in infants delivered by cesarean section placental transfusion is time related during the first 40 seconds of life and that maternal blood pressure also influences the magnitude of placental transfusion during the first 20 seconds after birth. Analysis of data from this study combined with data from a previous study shows that after 40 seconds the net flow between placenta and infant reverses and that cord clamping delayed beyond this point is accompanied by a rise in RPBV back to the level found when the cord was clamped before 20 seconds.
我们测量了20例未临产行剖宫产术分娩的足月婴儿的残余胎盘血量（RPBV）。所有病例中，脐带在出生后40秒内被夹紧。RPBV随着脐带夹紧时婴儿年龄的增加而显著降低。此外，出生后20秒内夹紧脐带的婴儿的RPBV与母亲收缩压呈负相关（平均RPBV在105托时为每千克54.8毫升，在148托时为每千克28.4毫升）。然而，对于20名婴儿的整个组或出生后20秒后夹紧脐带的婴儿，RPBV与母亲血压无关。这些数据表明，在剖宫产分娩的婴儿中，出生后前40秒内胎盘输血与时间相关，并且母亲血压在出生后前20秒内也影响胎盘输血的量。对本研究数据与先前一项研究数据的分析表明，40秒后胎盘与婴儿之间的净血流方向逆转，并且脐带夹紧延迟超过此时会伴随着RPBV上升回到在20秒前夹紧脐带时发现的水平。
