Retained placenta is a condition where all or part of the placenta

Placenta

The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...

 or membranes are left behind in the uterus

Uterus

The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...

 during the third stage of labour.

In humans

In humans, retained placenta is generally defined as a placenta that has not undergone placental expulsion

Placental expulsion

Placental expulsion occurs when the placenta comes out of the birth canal after childbirth. The period from just after the fetus is expelled until just after the placenta is expelled is called the third stage of labor....

 within 30 minutes of the baby’s birth.

Risks of retained placenta include hemorrhage and infection.

Management

Stimulation of uterine contractions by an intraumbilical or intramuscular oxytocin injection appears to be a useful and inexpensive non-surgical and non-aggressive method of inducing placental expuslion. It is also useful ensuring the bladder is empty. However, ergometrine should not be given as it causes tonic uterine contractions which may delay placental expulsion. Controlled cord traction has been recommended as a second alternative after more than 30 minutes have passed after stimulation of uterine contractions, provided the uterus is contracted. Manual extraction may be required if cord traction also fails, or if heavy ongoing bleeding occurs. Very rarely a curettage is necessary to ensure that no remnants of the placenta remain (in rare conditions with very adherent placenta such as a placenta accreta

Placenta accreta

Placenta accreta is a severe obstetric complication involving an abnormally deep attachment of the placenta, through the endometrium and into the myometrium...

.

However, in birth centers and attended home birth environments, it is common for licensed care providers to wait for the placenta's birth up to 2 hours in some instances.

In cattle

Retention

Retention

Retention may refer to:* Retention, in learning, the ability to retain facts and figures in memory ** Selective retention* Cultural retention* Customer retention...

 of fetal membranes

Fetal membranes

The fetal membranes, or chorioamniotic membranes, are the amnion and chorion which surround and protect a developing fetus....

(afterbirth) is observed more frequently in cattle, than in other animals. In a normal condition, a cow’s placenta is expelled within a 12-hour period after calving.