Widnes Christian, Flo Kari, Acharya Ganesh
Women's Health and Perinatology Research Group, Department of Clinical Medicine, Faculty of Health Sciences, UiT-The Arctic University of Norway and Department of Obstetrics and Gynaecology, University Hospital of North Norway, Tromsø, Norway.
Women's Health and Perinatology Research Group, Department of Clinical Medicine, Faculty of Health Sciences, UiT-The Arctic University of Norway and Department of Obstetrics and Gynaecology, University Hospital of North Norway, Tromsø, Norway.
Placenta. 2017 Jan;49:16-22. doi: 10.1016/j.placenta.2016.11.005. Epub 2016 Nov 12.
Placental blood flow is closely associated with fetal growth and wellbeing. Recent studies suggest that there are differences in blood flow between male and female fetuses. We hypothesized that sexual dimorphism exists in fetal and placental blood flow at 22-24 weeks of gestation.
This was a prospective cross-sectional study of 520 healthy pregnant women. Blood flow velocities of the middle cerebral artery (MCA), umbilical artery (UA), umbilical vein (UV) and the uterine arteries (UtA) were measured using Doppler ultrasonography. UV and UtA diameters were measured using two-dimensional ultrasonography and power Doppler angiography. Volume blood flows (Q) of the UV and UtA were calculated. Maternal haemodynamics was assessed with impedance cardiography. UtA resistance (R) was computed as MAP/Q.
UA PI was significantly (p = 0.008) higher in female fetuses (1.19 ± 0.15) compared with male fetuses (1.15 ± 0.14). MCA PI, cerebro-placental ratio (MCA PI/UA PI), Q UtA PI, Q and R were not significantly different between groups. At delivery, the mean birth weight and placental weight of female infants (3504 g and 610 g) were significantly (p = 0.0005 and p = 0.039) lower than that of the male infants (3642 g and 634 g).
We have demonstrated sexual dimorphism in UA PI, a surrogate for placental vascular resistance, at 22-24 weeks of gestation. Therefore, it would be useful to know when this difference emerges and whether it translates into blood flow differences that may impact upon the fetal growth trajectory.
胎盘血流与胎儿生长及健康密切相关。近期研究表明，男、女胎儿的血流存在差异。我们推测在妊娠22 - 24周时，胎儿及胎盘血流存在性别差异。
这是一项对520名健康孕妇的前瞻性横断面研究。使用多普勒超声测量大脑中动脉（MCA）、脐动脉（UA）、脐静脉（UV）和子宫动脉（UtA）的血流速度。使用二维超声和能量多普勒血管造影测量UV和UtA的直径。计算UV和UtA的容积血流量（Q）。用阻抗心动图评估母体血流动力学。UtA阻力（R）计算为平均动脉压/MCA。
与男胎（1.15±0.14）相比，女胎（1.19±0.15）的UA搏动指数（PI）显著更高（p = 0.008）。两组之间MCA PI、脑胎盘比值（MCA PI/UA PI）、Q、UtA PI、Q和R无显著差异。分娩时，女婴的平均出生体重（3504g）和胎盘重量（610g）显著低于男婴（3642g和634g）（p = 0.0005和p = 0.039）。
我们已经证明在妊娠22 - 24周时，作为胎盘血管阻力替代指标的UA PI存在性别差异。因此，了解这种差异何时出现以及它是否转化为可能影响胎儿生长轨迹的血流差异将是有用的。
