The pain of a posterior fornix puncture is essentially the same as that of an intramuscular drug injection, but a posterior fornix puncture will be quicker and the pain will be relatively short-lived. Most posterior fornix punctures are used when there is suspicion of internal bleeding, to draw out fluid from the pelvis, to see if it is blood or inflammation, and to determine if it is an ectopic pregnancy, a ruptured corpus luteum, or a large amount of fluid from inflammation, taking into account the history of the pregnancy. If necessary, a posterior fornix puncture can be performed to further clarify the diagnosis. After the posterior fornix puncture, make sure to keep the vulva clean to avoid local infection, and it is also recommended not to have sex for half a month after the posterior fornix puncture.