Retained placenta is a complication of the third period of labor, a condition in which the placenta does not completely or partially peel off from the uterine walls. Clinically, it may manifest itself as pathological bleeding or the absence of bloody discharge normal for this period, soreness or lack of attempts. At the same time, the standing of the uterine floor corresponds to the period after the expulsion of the fetus, the connection of the umbilical cord with the uterus is indirectly determined. The diagnosis is established on the basis of the results of physical examination, ultrasound. Most often, manual separation of the afterbirth or surgical treatment is performed.
O73 Retention of the placenta and fetal membranes without bleeding
According to the WHO definition, retained placenta is diagnosed if the detachment does not occur within half an hour after the end of the second period of labor. The incidence of pathology is 0.8-1.2% of all births. This complication is more often registered in repeat births, especially those with a history of cesarean section. The disease is a serious problem of modern obstetrics, as it is often accompanied by postpartum bleeding. Bleeding is the cause of maternal mortality in a quarter of cases, 30% of which are the result of retained placenta.
The etiology of retained placenta has not been definitively studied. Violations of the detachment of the placenta and its parts in the subsequent period, on the one hand, may be due to defects in uterine contractile activity, on the other – excessively tight attachment of the baby’s place. In most women in labor, it is not possible to detect any visible disorders. The main causes of pathology include:
- Hypotension of the uterus. Weak contractions of the uterine muscles are not enough to start the process of separation of the afterbirth, even if the placenta does not have specific features that prevent detachment. In the presence of predisposing conditions, a slight decrease in contractile function can become a trigger factor for the development of pathology.
- Tight attachment of the placenta. It is caused by the depletion of the basal layer of the decidual membrane and is characterized by a stronger than normal connection with the uterine walls without the germination of chorionic villi into the myometrium. In the pathology under consideration, the strength of uterine contractions is not enough to completely separate the afterbirth, which leads to bleeding.
- The true increment of the placenta. It is also associated with the underdevelopment of the basal layer, but in this case there is an invasion of villi into the muscle tissue, and in rare cases, the serous lining of the uterus. It is more common with placenta previa. Spontaneous detachment of the grown-up child’s place is impossible, manual separation can lead to perforation of the uterine wall.
- Anomalies of placental development. Delayed detachment is often observed with anomalies of development (lobed, two- and three-lobed or having additional lobules) of the placenta. The separation of the afterbirth is difficult with the so-called “filmy” placenta, characterized by an insignificant thickness and a large area of attachment, often extending to the entire uterine wall.
The most significant risk factors are endometritis suffered before pregnancy, features of obstetric history (operations on the uterus, abortions, multiple births), indicating traumatic injuries. Inflammation and trauma lead to anatomical and histological changes in the uterus, which negatively affects placentogenesis, myometrial tone. Predisposing conditions include hyperandrogenism, malformations of the uterus (bicornuate uterus, septate uterus), bulky formations (fibroids, nodular adenomyosis).
Normally, after the birth of the fetus, subsequent contractions appear, in which contractions extend to the entire uterus, including the placental pad (previously, the musculature of this zone did not function). Labor activity leads to the detachment of the child’s place in the area of the spongy layer of the mucosa (with the preservation of the basal layer), and then – to its exit outside. The separation of the afterbirth is accompanied by vascular damage, physiological bleeding. After his birth, the uterus contracts, which helps to stop the bleeding.
In the presence of adverse factors and predisposing conditions, detachment is difficult. With partial detachment, if the process has begun, but for some reason has stopped, the gaping vessels of the uncorrupted uterus become a source of pathological blood loss. The ingrowth of chorionic villi deep into the myometrium leads to thinning of the uterine wall, so an attempt to separate the placenta manually quickly ends with trauma, accompanied by intense bleeding.
The subjective signs of retained placenta include prolonged, painful unsuccessful attempts after the birth of a child or their complete absence. An objective sign is intense bleeding observed during partial separation. If the detachment of the afterbirth does not occur at all, even in partial volume (for example, with full increment), bloody discharge from the birth canal may be absent.
The most common complication of retained placenta is bleeding. Significant blood loss leads to such a potentially fatal complication as hemorrhagic shock, accompanied by multiple organ failure. Massive bleeding often develops with untimely provision of professional medical care (the risk increases sharply during childbirth outside a medical institution).
Other frequent complications of this pathology include purulent-inflammatory diseases (postpartum endometritis, pelvioperitonitis, obstetric sepsis), which can be both a consequence of surgical treatment and the delay of fragments of the afterbirth in the uterine cavity. In addition, the remaining ingrown placenta can become a source of late postpartum bleeding, rupture of the uterus during subsequent pregnancy.
The diagnosis of retained placenta is made by an obstetrician if the discharge of the afterbirth did not occur within thirty minutes after the birth of the baby with the appropriate results of physical examination. Ultrasound examination is additionally used to determine the causes of the pathological condition (on which the choice of therapeutic tactics depends).
- Clinical examination. Signs of retained placenta are determined by the shape and location of the uterus, the mobility of the umbilical cord. If separation has not occurred, the uterus has a rounded shape, the bottom is located at the navel (a sign of a Shredder), the outer segment of the umbilical cord does not lengthen (a sign of an Alfeld). The umbilical cord is retracted when pressing over the womb (a sign of Kustner-Chukalov), after inhalation (a sign of Dovzhenko), pushing (a sign of Klein).
- Ultrasonography. Ultrasound of the uterus is prescribed to diagnose placental increment. Ultrasound signs of this pathology include deformation of the inner contour of the uterine cavity, its uneven expansion, and the absence of a hypoechoic layer between the myometrium and the placenta. Ultrasound angiography detects hypervascularization of the anterior wall, chaotic branching of blood vessels.
When the afterbirth is delayed, the volume of lost blood is estimated (pathological blood loss is over 400-500 ml). If a surgical operation is necessary, a coagulogram and a clinical blood test are examined. Differential diagnosis is carried out with a delay in the birth of the separated placenta, primarily with its infringement due to uneven or spastic contractions of the myometrium.
Therapeutic measures that contribute to the separation of the afterbirth are carried out only in the absence of pathological bleeding, and can last for 20-30 minutes. If conservative treatment is ineffective, surgical methods are used, in case of pathological blood loss, replacement hemotransfusion is performed. Therapy is aimed at strengthening uterine contractions and includes:
- Catheterization of the bladder. Since the muscular layer of the bladder is closely connected with the nerve fibers of the uterine musculature, irritation of the urothelium receptors leads to a reflex contraction of the myometrium. Catheterization normalizes the course of the postpartum period of labor, promotes timely separation and isolation of the afterbirth.
- Medications. To enhance labor activity, intravenous or intramuscular administration of uterotonic drugs is indicated (oxytocin preparations are preferred) in combination with traction for the umbilical cord. In parallel, intravenous transfusion of crystalloid solutions is carried out to correct probable blood loss.
Surgical treatment of delayed separation can be carried out by non-surgical or operative method. Treatment tactics depend on the cause that caused the pathology. Surgical intervention should be carried out in a timely manner, before the onset of generalized coagulopathy on the background of massive bleeding (otherwise, the operation aggravates the severity of the condition). In order to stop bleeding, embolization of the uterine vessels is used, hemostatic sutures are applied.
- Manual manual. With tight attachment of the baby’s place or other reasons for delaying its detachment (with the exception of true increment), manual separation of the placenta is performed with its subsequent output to the outside. In order to avoid traumatic shock, intravenous anesthesia is performed before manipulation. Antibiotics (penicillin, cephalosporin series) are used to prevent septic complications.
- Surgical operation. It is indicated with the ineffectiveness of conservative correction of bleeding, true increment. The volume can vary from organ-preserving surgery (excision of the area of a partially ingrown child’s place with an affected myometrium and subsequent plastic surgery) to radical (extirpation of the uterus, supravaginal amputation) with complete ingrowth, uncupable bleeding.
Prognosis and prevention
If adequate treatment is started in a timely manner, the prognosis for life is favorable. The possibility of further realization of the reproductive function largely depends on the presence of complications, the reasons for retained placenta. Primary prevention consists in the fight against abortions, the treatment of inflammatory diseases and the correction of endocrine disorders at the stage of pre-pregnancy preparation. An important aspect of secondary prevention is planned obstetric ultrasound during gestation, which allows early detection of placental increment, and the choice of delivery tactics.