Causes of retained placenta

Retained placenta will affect a woman's next pregnancy, and will affect the contraction of the uterus and symptoms of irregular menstruation and excessive bleeding, so we should understand the causes of retained fetus. The cause of retained fetus is mainly due to uncoordinated uterine contractions and uterine atony, and it may also be caused by the effects of drugs. Therefore, it is recommended that the cause of retained placenta should be properly dealt with.

Causes of retained placenta

There are many reasons for retained placenta clinically, the most common of which is the influence of uterine contraction factors. If uterine contractions are weak or uncoordinated, placental delivery will be affected, resulting in retained placenta. In addition, factors such as adhesion of the placenta and the uterine wall, obstruction of expulsion, and improper handling of the third stage of labor can also cause retained placenta.

1. Weak uterine contractions. After the fetus is delivered, if the mother's uterine contraction is very weak and not enough to completely separate the placenta, it may lead to retained placenta. This situation generally does not cause postpartum hemorrhage. If uterine contractions are relatively weak and the placenta is partially detached, it may also lead to retained placenta and heavy postpartum bleeding. The effects of uterine atony are also the most common cause of retained placenta.

2. Uncoordinated uterine contractions. Normal uterine contractions begin from the uterine horns on both sides. The contraction force first concentrates in the middle of the uterine fundus and then spreads to the lower part of the uterus, among which the contraction force at the uterine fundus is the strongest. If uterine contractions are uncoordinated and spasm or narrowing of the internal uterine opening occurs, the placenta may be retained in the uterine cavity.

3. Adhesion into placenta implantation. Part of the placenta is adhered to the uterine wall, or part of the placental villi grow into the uterine muscles, forming an implanted placenta. This can prevent the placenta from being completely separated from the uterus, leading to retained placenta and heavy bleeding. This situation is relatively rare and usually occurs in women who have given birth multiple times, had multiple abortions due to curettage, or have uterine cavity infection.

4. The expulsion of the placenta is obstructed. When the placenta and uterus have been completely separated, the placenta may be retained because of obstruction of expulsion due to factors such as weak abdominal muscle contraction, bladder fullness, etc.

5. Human factors. This is mainly due to improper management of the third stage of labor. A common situation is that the umbilical cord breaks when it is pulled. During the third stage of labor, some women need to be injected with oxytocin to increase uterine contractions. Through uterine contractions, the placenta can be separated from the uterine wall. At this time, the midwife will put one hand on the woman's belly to stabilize the uterus, and then use the other hand to slowly pull the umbilical cord. If the placenta has separated at this point, it will be easily delivered from the vagina. If the placenta has not been completely separated and the umbilical cord is relatively thin, it is easy to be torn off, causing the cervix to shrink and the placenta to be retained.