This can also be done prenatally by testing fetal DNA obtained through either chorionic villus sampling or amniocentesis.

这可以在产前通过检测胎儿DNA完成，如绒毛膜绒毛取样或羊膜穿刺术。

These are caused by overstimulation by human chorionic gonadotropin or hCG, a hormone that's produced by the placenta, so they're only seen in pregnancy.

这是由人体绒毛膜促性腺激素（hCG）过度刺激导致的；这种激素由胎盘释放，因此仅见于怀孕期间。

So, for example, a pinealoma may lead to increased secretion of the hormone beta human chorionic gonadotropin that can cause an early onset of puberty.

比如，松果体瘤可能导致β人绒毛膜促性腺激素分泌增加，可引起青春期发育提前。

Gases and nutrients move back and forth between the decidua basalis and the fetal veins, by diffusing through the tissue layer of the thin chorionic villi.

气体和营养物质通过在薄绒膜绒毛组织层之间扩散，在基蜕膜和胎儿静脉之间来回移动。

The fetal layer of the placenta on the other hand is called the chorion, which is a tissue that has fingerlike projections called chorionic villi which contain tiny fetal arterioles and venules.

胎盘的“胎儿层”也被称为绒毛膜；这是一种有绒毛膜绒毛这种手指状突起的组织，富含微小的胎儿动脉和静脉。

They began to notice a pattern of fluctuations throughout a woman's 28 day menstrual cycle and saw a sharp spike in the level of HCG (human chorionic gonadotropin) in pregnant women, and nowhere else.

他们开始注意到女性28天的月经周期中有一种波动模式，孕妇的 HCG（人绒毛膜促性腺激素）水平急剧上升，而其他人则不会。

AFP, though, can be elevated by other conditions as well, so in order to get a more exact diagnosis, additional blood tests for human chorionic gonadotropin, or HCG, inhibin A, and estriol, as well as an ultrasound are usually done.

但甲胎蛋白也会由于不少其它原因而升高，所以为了得到更准确的诊断，还需检查人绒毛膜促性腺激素（HCG）、抑制素A、雌三醇水平，或作超声检查。