Historical theories and modern perspective
Historically, two main concepts of pathogenesis have evolved, complementing each other in modern practice:
- Mechanical theory (proposed by Bandl in the late 19th century). Attributes the injury to an insurmountable mechanical obstruction to fetal descent amid strong, hyperactive uterine contractions.
- Functional theory (N.Z. Ivanov, Ya.F. Verbov, early 20th century). Links the pathology to degenerative and inflammatory changes in the myometrium. Historical fact: Ya.F. Verbov mistakenly denied the stage of impending rupture, which gave rise to the dangerous myth about the existence of "asymptomatic" ruptures.
Since the mid-20th century, a combined approach has prevailed. In developed countries, over 90% of cases are histopathic ruptures. Their primary cause is scar dehiscence following a previous Cesarean section or organ-sparing surgery (e.g., myomectomy). Due to connective tissue proliferation, the wall loses elasticity and tears apart as intrauterine pressure rises.
Classification
The most comprehensive classification was proposed by L.S. Persianinov (1964). It takes into account several key criteria:
- By pathogenesis: spontaneous (mechanical, histopathic, mechanohistopathic) and violent (traumatic, mixed).
- By nature of the injury: fissure (tear), incomplete rupture (does not penetrate the peritoneal cavity, forming a hematoma in the prevesical tissue or between the leaves of the broad ligament), and complete rupture (involving all layers with entry into the peritoneal cavity).
- By localization: in the fundus, body, lower segment, or detachment from the vaginal fornices.
- By clinical course: impending, in-progress (ongoing), and completed (actual) rupture.
Mechanical and violent factors
Mechanical ruptures occur exclusively during labor. Obstructions causing overdistention of the lower uterine segment include: an anatomically narrow pelvis, retroperitoneal tumors, fetal macrosomia, extension attitudes, asynclitism, and cicatricial strictures of the birth canal.
Violent (traumatic) ruptures are significantly less common today, but can be triggered by rough iatrogenic interventions:
- Application of obstetric forceps or destructive operations.
- Use of the prohibited Kristeller maneuver (expression of the fetus by pushing on the uterine fundus).
- Inadequate oxytocin stimulation (especially in multiparous women with a large fetus against the background of a pathologically altered uterine wall).
Clinical presentation of impending rupture
Symptoms are most pronounced after rupture of the amniotic membranes in the presence of a mechanical obstruction. The main pathogenetic factor is critical overdistention of the lower uterine segment.
Key objective signs:
- Hyperactive, sharply painful contractions without a relaxation phase.
- Pronounced maternal anxiety, tachycardia, and tachypnea.
- Difficulty urinating or blood in the urine (gross hematuria) due to compression of the urethra and bladder.
- The uterus assumes a hourglass shape: the retraction ring rises to the level of the umbilicus or higher, the upper part of the uterus is tightly contracted, while the lower segment is overdistended and extremely tender.
- Round ligaments are taut, tender, and positioned asymmetrically.
- On vaginal examination: full cervical dilation, absence of the amniotic sac. The fetal head is high, but a massive caput succedaneum forms on it, creating a false impression of its low station.
If emergency care is not provided, the stage progresses to in-progress (ongoing) rupture: muscle fiber tears appear, and a hematoma forms, which begins to dictate the subsequent clinical picture.
Briefly: answers to topical questions
What is the clinical presentation of an ongoing uterine rupture?
- Uterine hypertonus (hypertonus uteri) — the uterus is tense and fails to relax between contractions.
- Pain syndrome (dolor) — intensification of abdominal pain and pain in the area of the postoperative scar; pain may lack clear localization.
- Vaginal bleeding (haemorrhagia) — the appearance of blood from the genital tract confirms the diagnosis in 100% of cases.
- Fetal distress (distress foetus) — impaired placental blood flow leads to fetal hypoxia accompanied by bradycardia.
What symptoms are characteristic of a completed uterine rupture?
- Change in uterine shape (mutatio formae uteri) — formation of a pathological retraction ring resembling an "hourglass" sign.
- Labor arrest (disturbatio partus) — complete cessation of uterine activity or lack of labor progress.
- Fetal location (locatio foetus) — palpation or visualization of fetal parts in the maternal abdominal cavity.
- Pain syndrome and deterioration of general condition (dolor et deterioratio status generalis) — pain persists between contractions, with a risk of pain-induced shock; psychomotor agitation and deterioration of vital signs are possible.
The "hourglass" rule: if amid hyperactive, unremitting contractions the mother's abdomen takes on an hourglass shape (due to an elevated retraction ring), and blood appears in the urine, this is the classic picture of an impending mechanical rupture.
Class and exam questions
What is the difference between a complete and an incomplete uterine rupture?
A complete rupture penetrates all layers of the uterine wall directly into the peritoneal cavity. An incomplete rupture does not damage the peritoneum; it occurs in areas of its loose attachment (e.g., along the uterine margin), and the extravasating blood accumulates as a hematoma in the parametrial tissue.
Why do histopathic uterine ruptures occur?
They are caused by dystrophic changes in the myometrium, where muscle and elastic fibers perish and are diffusely or locally replaced by rigid connective tissue. Most commonly, this is a consequence of a prior Cesarean section, grand multiparity, or previous endomyometritis.
What is the Kristeller maneuver and why is it dangerous?
This is an obstetric maneuver in which strong physical pressure is applied manually to the uterine fundus to accelerate fetal expulsion. This intervention is a crude iatrogenic factor and can provoke a traumatic uterine rupture.
Can a uterine rupture occur before the onset of labor?
Yes, histopathic ruptures (e.g., along a dehiscent postoperative scar) can occur even during pregnancy due to the gradual increase in intrauterine pressure and stretching of the wall as the fetus grows.
What else to study on this topic
- Clinical presentation of a completed uterine rupture
- Differential diagnosis with placental abruption (abruptio placentae)
- Management of pregnancy and labor in patients with a uterine scar
- Cervical lacerations: classification by degree and repair techniques
- Pubic symphysis separation during childbirth: clinical features and management
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