Which of the following can cause uterine inversion?

Uterine inversion occurs when the uterus turns inside out, which is a serious complication typically occurring after childbirth. The primary factor often involved in uterine inversion is related to improper handling of the uterus, particularly during procedures like fundal massage. Proper fundal massage is performed to help the uterus contract and minimize bleeding after delivery. However, if the massage is done too vigorously or incorrectly, it can lead to the uterus being pulled down and inverted.

Other options, while they may relate to labor and delivery complications, are not direct causes of uterine inversion. For example, excessive fetal movement typically does not impact the positioning of the uterus significantly. Prolonged labor can contribute to other complications, but it does not directly factor into uterine inversion. Similarly, the use of analgesics during labor is aimed at managing pain and does not generally correlate with causing inversion of the uterus. Thus, the context of uterine inversion identifies improper fundal massage as the critical factor that can result in this serious condition.