This in turn prevents effective uterine contractions, and leads to uterine atony.

胎盘组织残留会阻碍宫有效收缩，而导致宫缩乏力。

But if it does happen, the resulting uterine contractions and increased lubrication can help draw up and hold sperm in the uterus.

但是如果真发了，由此产宫收缩润滑增加有助于在宫中吸收保持精。

The amount of bleeding can vary, and it can be intermittent or continuous, sometimes increasing during labor because of uterine contractions and cervical dilation.

血量不等，可能是间断或血，有时在产时由于宫颈扩张，血量会增多。

Power refers to forceful uterine contractions, passenger refers to the fetus, and passage refers to the route that the fetus has to travel through the bony pelvis.

产力指有力宫收缩，娩物指胎儿，产道指胎儿穿过骨盆路径。

It can also occur when a woman is unable to empty her bladder, since a full bladder can push against the uterus and interfere with uterine contractions.

不仅如此，膀胱排空障碍也能引起产后宫收缩乏力，因为充盈膀胱将推挤宫，进而阻碍宫有效收缩。

Finally, some commonly used obstetric medications such as anesthetics (especially halothane), magnesium sulfate, nifedipine, and terbutaline can all interfere with uterine contractions and increase the risk of uterine atony.

此外，一些产科常用药物如麻醉药（特别是氟烷）、硫酸镁、硝苯地平特布他林等也会影响产后宫正常收缩，增加宫缩乏力风险。