Uterine subinvolution is a postpartum complication characterized by a slowdown in the recovery of normal (prenatal) uterine dimensions. Symptoms are abundant brown spotting, subfebrile body temperature, absence of the usual cramping pains during breastfeeding. The presence of complications is determined by gynecological examination, ultrasound (ultrasound of the uterus, three-dimensional echography). The treatment is complex, including hormonal drugs – stimulators of myometrial contraction, antibiotics or antiviral agents. To stimulate involution, blood clots are removed from the uterus, gynecological massage is performed.
N85.3 Uterine subinvolution
The prefix “sub” in the term “subinvolution” means incomplete or partial involution (restoration) of the uterus after childbirth. It is a fairly frequent postpartum complication – it is registered in 1-2% of women in labor, and among all pathologies after childbirth, its share is 30-50%. There is a scientific debate as to whether this condition should be considered a separate nosological unit. Many experts attribute it to the first manifestations of postpartum endometritis – to the group of infectious complications after childbirth. According to another point of view, subinvolution is an independent disease caused by bacterial or viral infection and almost always leads to endometritis.
Causes of uterine subinvolution
The point of view generally recognized in obstetrics calls infectious inflammation of bacterial or viral nature the direct cause of the development of pathology. But the very presence of infection does not guarantee the development of complications, therefore, a number of predisposing factors are identified. The degree of their influence varies among different women, which makes it difficult to identify a clear correlation. There are the following circumstances that contribute to the development of such a postpartum condition:
- Delay of parts of the afterbirth. Fragments of the placenta, fetal bladder or blood clots remaining in the uterine cavity are almost always detected during subinvolution. It is believed that this condition facilitates infection of the genitals with the development of endometritis and slowing the recovery of the uterus.
- Pathology of pregnancy. Polyhydramnios, large fetuses, and multiple births are predisposing factors to the development of such a complication. In addition, inflammatory diseases during pregnancy (pyelonephritis, cystitis) also increase the risk of developing postpartum pathology.
- Birth anomalies. Prolonged or rapid labor is a risk factor for this complication in the postpartum period.
- Constitutional features of a woman. There is an opinion that the reduced contractile activity of the myometrium is due to the genetic and individual characteristics of the female body. In such women, the probability of this postpartum complication is several times higher.
In addition to the above predisposing factors, some researchers have noted an increased incidence of subinvolution against the background of uterine fibroids, young (less than 18 years old) or the older reproductive (more than 40 years) age of the woman in labor. The absence of breastfeeding during the first 4-5 days after the birth of a child increases the likelihood of such a complication – this is due to the lack of hormonal stimulation during natural feeding. The wrong location of the uterus, disorders of its ligamentous apparatus, anemia and systemic diseases can play a role.
The main role in the pathogenesis of uterine subinvolution is played by several factors – a decrease in the contractile activity of the myometrium, long-term preservation of postpartum tissue edema, slowing down the lysis of collagen fibers. The contraction of muscle fibers slows down as a result of their overextension during pregnancy or due to weak neurohumoral stimulation. This mechanism is the leading one in the true forms of complication. A decrease in contractility not only slows down recovery, but also indirectly facilitates the penetration of infection onto the damaged surface of the endometrium, leading to endometritis.
The reverse development of the internal genitalia normally occurs not only due to the reduction of the muscle layer, but also due to a decrease in tissue edema. In the first period after childbirth, the surface of the endometrium has a wound character, but within 4-10 days it heals with a decrease in swelling due to spasm and “twisting” of blood vessels. But in the presence of foreign bodies in the organ cavity or tissue infection, the resulting inflammation contributes to the preservation of edema and the occurrence of microcirculatory disorders. Against this background, the splitting of collagen fibers also slows down, but no clear and reliable explanations for this phenomenon have yet been found.
There are several types of classification of subinvolution in obstetric practice, but most of them are not widely used. The complexity of the classification is due to a number of circumstances – the abundance of mechanisms for the development of the condition, the lack of reliable data on the role of concomitant pathologies (late gestosis, inflammation of the genitourinary system). Therefore, only one type of classification of this postpartum complication is used, which is based on the immediate causes of the pathology:
1 Primary or true type. It is less common than other types of uterine subinvolution. Such a diagnosis is made when the recovery of the organ slows down against the background of a complete absence of signs of bacterial or viral infection. Within this type , there are three subgroups:
- Myogenic subtype. Slow involution is mainly due to overgrowth or weakness of the myometrium. This condition is observed after pregnancy, which proceeded with polyhydramnios, a large fetus, with rapid or prolonged childbirth.
- Microcirculatory subtype. The cause of this type of disease is the slow restoration of the uterine circulatory network and the preservation of tissue swelling. In this case, the pathology can be provoked by late gestosis, insufficient emptying of the bladder and rectum before childbirth.
- Endocrine subtype. Occurs with insufficient neurohumoral stimulation of the reproductive system after childbirth. It can be caused by both endocrine pathologies and the absence of breastfeeding during the first few days of a child’s life.
2 Infectious type. It is the cause of most cases of subinvolution, some experts consider it not as a separate condition, but as one of the stages of postpartum endometritis. It is caused by inflammatory processes caused by viral or bacterial pathogens, including opportunistic flora. The risk of complications increases in the presence of foci of infection in the body (pyelonephritis, cystitis), delay of the remnants of the afterbirth in the uterine cavity.
Symptoms of uterine subinvolution
The first symptom of the disease is the presence of bloody discharge (lochiae), often abundant, brown in color. A pathognomonic sign is the persistence of bleeding until the late postpartum period (3-4 weeks). Obstetricians recognize the absence of cramping pains in the lower abdomen when breastfeeding as an indirect symptom of pathology. Sometimes pulling pain sensations may be registered that are not related to the feeding regime or other external factors. The presence of these manifestations in combination with predisposing factors in the anamnesis indicates the presence of a violation.
The infectious type of the disease has the features of postpartum endometritis – chills develop (in severe cases – fever), body temperature ranges from subfebrile to high (39-40 °C) values. The change in the nature of lochia from bloody to purulent indicates the development of severe inflammation of the inner lining of the uterus. There is soreness of the anterior abdominal wall, tachycardia, symptoms of general intoxication – headaches, weakness, nausea. The severity of symptoms in this case depends on the nature of the pathogen, the reactivity of the woman’s body and a number of other circumstances.
Any type of uterine subinvolution without proper treatment sooner or later leads to infectious complications – endometritis or endomyometritis. Even with the true type of complication, there are no signs of infectious inflammation only at first, but the slowdown in the recovery of the organs of the reproductive system makes them vulnerable to pathogenic microflora, including conditionally pathogenic. Endometritis can be complicated by sepsis, peritonitis, septic shock and other infectious processes. Less often, this condition can lead to metrothrombophlebitis, embolism of the vessels of the internal genital organs, severe uterine bleeding.
Obstetricians and gynecologists already at the stage of pregnancy identify a risk group among women who are more likely to develop subinvolution. It includes pregnant women with polyhydramnios, fibroids, large fetuses, infectious and inflammatory pathologies of the genitourinary system, pronounced signs of gestosis. Such women need special monitoring in the postpartum period for the timely detection of complications and the beginning of their treatment. A range of obstetric studies and general clinical analyses are used to diagnose the condition:
- Consultation of an obstetrician. The specialist conducts an inquiry, during which he determines the nature, volume and duration of lochies, the presence or absence of subjective symptoms. Based on the data obtained, the doctor prescribes a number of additional diagnostic procedures.
- Examination on the chair. Bimanual examination reveals an enlargement of the uterus (not matching the term after childbirth), a pear-shaped spherical shape of the organ. The elastic-soft consistency indicates the presence of remnants of the afterbirth in the birth canal. When examined by mirrors, the swelling and purplishness of the neck is determined, the cervical canal is enlarged (1-2 fingers pass easily), blood clots are detected in its cavity.
- Ultrasound examinations. To diagnose the complication, transabdominal and transvaginal ultrasound of the pelvic organs, three-dimensional echography are used. The high standing of the uterine floor, which does not correspond to the postpartum period, thickening of its walls is determined. Echography allows you to accurately determine the presence of foreign bodies and remnants of the afterbirth in the uterine cavity.
- Hysteroscopy. Endoscopic examination of the internal cavity of the uterus often reveals signs of subinvolution and endometritis even before the height of clinical manifestations. In addition to the examination, the technique makes it possible to take samples of the endometrium, lochia, afterbirth remnants for more accurate diagnosis.
With the infectious form of the disease or the addition of complications, clinical blood and urine tests are also prescribed as diagnostic procedures, sometimes the microflora of the vagina or uterus is seeded (with endometritis) to determine the pathogen. Changes characteristic of inflammatory processes are detected in the blood – increased ESR, leukocytosis, anemia. In recent years, a tomographic method – MRI of the pelvic organs – has also been used for diagnosis. It allows you to accurately determine the size and structure of the uterus and identify even the smallest pathological inclusions in its cavity.
Treatment of uterine subinvolution
The therapy of the condition is complex, including medication, instrumental and massage procedures. An important role in the effectiveness of therapeutic measures is played by determining the type of disease, and with its infectious nature – the type of pathogen. The duration of treatment depends on the severity of the symptoms of pathology and the presence or absence of concomitant diseases that can affect the organs of a woman’s reproductive system. Effective therapy of subinvolution includes such drugs and treatment methods:
- Hormonal agents. Uterine contraction after childbirth normally occurs under the influence of the hormone oxytocin. Therefore, hormonal drugs that affect the myometrium and its vessels – oxytocin, methylergometril and others – are used to accelerate this process.
- Antibacterial therapy. The most common cause of infection in the postpartum period is bacterial microflora. To eliminate it, broad-spectrum antibiotics are used. If, as part of the diagnosis, it was possible to determine the type of pathogen, antibiotic therapy is carried out with the most appropriate drug in this case.
- Removal of inclusions in the uterus. The remnants of the afterbirth and blood clots facilitate infection and can themselves cause inflammation. They are eliminated by vacuum aspiration or by curettage of the uterine cavity.
- Gynecological massage. It is able to improve the contractile properties of the myometrium and accelerate the recovery of the reproductive system after childbirth.
- General winter events. A woman with a subinvolution of the uterus is shown bed rest, lack of physical exertion and emotional stress. Regular application of the newborn to the breast also contributes to the reduction of the myometrium.
Prognosis and prevention
Subinvolution of the uterus before the development of severe infectious complications responds well to therapeutic measures and is eliminated within a few weeks, therefore it has a relatively favorable prognosis. The development of endometritis and other inflammatory conditions against this background is fraught with more serious consequences – the occurrence of sepsis, infection of other organs and systems (abdominal cavity, urinary tract). Obstetricians recommend carrying out preventive measures for women whose pregnancy and childbirth took place with complications (polyhydramnios, rapid childbirth). They consist in the appointment of hormonal drugs to accelerate the involution in the first days after the birth of the child, regardless of the presence of symptoms of slowing the recovery of the uterus.