Therefore, you need to get your oxygen from the mother's placental blood flow and all that stuff.

因此，你需要从母亲的胎盘血流和所有的东西中获得氧气。

As the pregnancy progresses, the lower uterine segment grows, and if the placenta's in the lower uterus, this growth disrupts the placental blood vessels, which can cause bleeding.

随着孕程进展，子宫下部不断增长，而倘若胎盘在子宫下部，此时会引起前置胎盘的血管撕裂，进而导致出血。

Also use of certain drugs are risk factors, like cocaine and methamphetamine because these can cause significant vasoconstriction of the placental blood vessels and an abrupt increase in blood pressure, increasing the risk of an abruption.

危险因素还有使用某些药物，如可卡因、脱氧麻黄碱，因为它们会导致胎盘血管的收缩和血压的突然升高，增加胎盘剥离的风险。