A retained placenta is a relatively rare complication that can occur during the third stage of labor where the placenta is retained inside the body instead of being delivered. In one to every 100 or 200 births, the placenta is not delivered as expected and medical intervention is required to remove it. Retained placenta can be dangerous but is usually caught in time by alert midwives, doctors, and nurses.
The third stage of labor lasts from the delivery of the newborn to the expulsion of the placenta, also known as the afterbirth. Most women deliver the placenta within an hour of delivering the baby and in some cases, it may follow mere minutes after the birth. When it is not delivered naturally, medications can be used to stimulate uterine contractions to push it out, women can be massaged to encourage contractions, or the placenta can be removed manually by a care provider.
There are a number of reasons for this complication to occur. One is uterine atony, where the uterus goes slack after delivery instead of contracting to push out the placenta. Another reason is a trapped placenta, where the placenta gets stuck behind the cervix, an especially common problem if the umbilical cord is pulled out of the placenta. Placenta accreta, where part of the placenta is deeply embedded in the uterine wall, can be another reason for a woman to have a retained placenta. Women who have experienced this complication in prior labors are likely to develop a retained placenta again, as well.
Sometimes the entire placenta is left inside the uterus and in other cases, only part is delivered. The risks or a retained placenta are twofold. In the first place, the woman can bleed, sometimes very heavily, because the uterus is not contracting and returning to normal size. Secondarily, women are at risk of uterine infections caused by the breakdown of the placental material left inside the uterus.
The signs of a retained placenta are usually evident to a care provider. Depending on a woman's birth plan, the interventions recommended or offered may vary. Women undergoing managed labor may be given medications to stimulate contractions and expel the placenta, for example, while women seeking natural birth might be encouraged to breastfeed immediately, as this sometimes triggers contractions, or to take herbal preparations. If the placenta cannot be delivered after these minimally invasive interventions, a midwife or doctor will need to enter the uterus to take it out.