What describes a uterine inversion?

A uterine inversion occurs when the uterus turns inside out, typically during or after the delivery of a baby. This condition can lead to serious complications, such as severe bleeding and shock, as the uterus is unable to contract effectively after being inverted. The mechanism behind uterine inversion often involves a combination of factors including excessive traction on the umbilical cord or inadequate uterine tone following delivery.

The other options relate to different obstetric conditions. For example, premature detachment of the placenta refers to placental abruption, where the placenta detaches from the uterine wall before delivery, which is distinct from an inversion. Abnormal implantation of the placenta refers to conditions such as placenta previa or accreta, while excessive expansion of the uterus typically relates to issues like polyhydramnios or multiple pregnancies but does not describe the physical turning inside out characteristic of uterine inversion. Therefore, the option describing the uterus turning inside out accurately captures the essence of uterine inversion.