Incarceration of the gravid uterus: a case report and literature review

The condition of a gravid uterine incarceration has no clearly identifiable causes, but is strongly correlated to malposition of the nonpregnant uterus, which is typically retroversion. In most cases, the gravid uterus transforms from a pelvic organ to an abdominal organ and the retroverted uterus corrects itself as the fundus rising out of the pelvis between 12 and 14 weeks of gestation and spontaneously falling forward to its normal anatomical position. On rare occasions, the uterus remains in a retroverted position and is trapped in the pelvic cavity. Multiple factors have been identified to prevent the uterus from entering the abdominal cavity, including tumor, uterine malformation, pelvic adhesions secondary to abdominal surgery, inflammation in the pelvis, and endometriosis. Among the 136 patients reviewed, 3 patients had uterine anomalies (didelphic uterus 2 [18, 69] and bicornuate uterus 1 [59]); 1 had abdominal surgery and presented with serious pelvic adhesion [52]; 1 had a deep sacral concavity [77]; and 1 had a history of cystitis [27]. Two patients reported no special history [62, 80] and the risk information was not available for 2 patients [33, 82]. Uterine prolapse, deep sacral concavity, and uterine fibroids are also identified as significant risk factors for a gravid uterus to develop incarceration [68, 77, 80]. It is noteworthy that there were 10 cases of recurrent incarceration [18, 27, 33, 52, 59, 62, 69, 77, 80, 82]. It appears that pregnant women who had experienced incarceration, especially those with known risk factors discussed above are likely to develop recurrent incarceration during the subsequent gestation.

Eight patients became pregnant through ART [63, 64, 66, 77, 82, 93] and carried significant risk factors for incarceration. There is no definitive report that associates incarceration in pregnant women with ART, but common risk factors associated with incarceration, such as endometriosis or pelvic inflammatory diseases, have also been identified for infertility. Gravid uterine incarceration should therefore be considered if a pregnant woman through ART develops abdominal pain and vaginal bleeding. Since woman with ART often receive more extensive monitoring during their pregnancies, gravid uterine incarceration may be diagnosed early and a timely manner, leading to fewer complications. In fact, 7 patients in sporadic case reports who successfully delivered infants because of prompt diagnosis through pelvic examination and abdominal imaging. Our patient had a history of lymphatic tuberculosis that could result in pelvic adhesion and bilateral tubal blockage, both of which could contribute to the development of uterine incarceration.

Among the 162 reviewed cases, gravid uterine incarceration is mostly diagnosed in the second trimester. The symptoms of gravid uterine incarceration vary, but include urinary manifestations (53.70%, urinary retention, frequent urination, dysuria, urgency and paradoxical incontinence), abdominal pain (35.80%), constipation (6.79%), vaginal bleeding (6.17%), pelvic pain (6.79%), back pain (4.94%), tenesmus (1.85%), perineal pain (0.62%), and large painful mass prolapsed outside the anus (0.62%). Fourteen patients (8.64%) are asymptomatic, but also have delivered viable infants in the end, indicating that asymptomatic patients may better outcomes of pregnancy compared to those with severely symptomatic. Clinical complications usually occur after twelve weeks of gestation and are mostly related to the pressure from anatomical structures adjacent to the entrapped uterus, including lower abdominal and pelvic pain, dysuria, urinary frequency, urinary retention, overflow incontinence, rectal pressure, and worsening constipation [66, 92]. Among these, urinary retention is the most common symptom that occurs because of elongation of the urethra by displacement of the cervix, loss of the urethrovesical angle, and mechanical compression of the bladder neck. If an incarcerated uterus is not diagnosed and treated promptly, we speculate that bladder rupture, renal failure, spontaneous abortion, intra-uterine growth retardation, prematurity and premature rupture of the membranes, or even uterine sacculation or rupture may happen frequently.

Diagnosis of uterine incarceration remains difficult because its symptoms are often non-specific and absent in early pregnancy [82]. It is worth noting that in case reports, all diagnoses were made by clinical suspicion alone before 1969, but after 1974, especially after 2000, an increasing number of cases benefited from pelvic examination combined with imaging methods based on suspected symptoms. This could be explained by advances in imaging technology in recent years, which also indicated that ultrasound scanning or MRI facilitated early recognition and appropriate treatment of uterine incarceration.

In general, the features of pelvic examination can be described as follows. The cervix is anteriorly transfixed behind the pubic symphysis, making it difficult to expose. Additionally, sacculation of the posterior wall of the vagina and posterior fornix bulge may be observed, and the fundus is palpable within the curvature of the sacrum and could not be moved. Ultrasound examination could confirm incarceration. Abdominal sonography shows an advantage over transvaginal sonography in exhibiting the position of the cervix and its internal ostium and in determining the relationships between vagina, uterus and bladder, when the cervix is elongated and wedged behind the symphysis [80]. MRI is superior to ultrasound in the detailed scanning of gravid uterus incarceration [103]. It is suggested that every pregnant woman with an incarceration of the uterus should have MRI [104]. However, if the diagnosis is not suspected, the imaging findings can be misinterpreted as an intraperitoneal pregnancy, placenta previa or incorrect fetal presentation [88]. For our case, bloody vaginal discharge occurred at 15 weeks and 2 days of gestation, and urinary retention followed in the 16th week gestation. Even worse, this patient was misdiagnosed with a low position of the placenta based on an incorrect interpretation of the ultrasound scan in a local hospital.

No single treatment can be deemed more successful than the others for gravid uterus incarceration. Most obstetricians tend to replace the uterus in its natural position as soon as possible after diagnosis [80]. According to the gestational age, various management options may be considered. When incarceration of the retroverted gravid uterus is diagnosed in the late early trimester or early second trimester, obstetricians should fully evaluate the possibility of turning the uterus to a normal position. A passive reduction from a repeated knee-chest position after emptying the bladder can be recommended before 14 weeks of gestation. Between 14 and 20 weeks, the patient can also attempt a knee-chest position. If this method is unsuccessful, manual manipulation can be attempted. It is recommended to do this maneuver before 20 weeks of gestation, for more complications such as preterm labor may be caused by manual manipulation later than 20th week of gestation [105]. All maneuvers should only be performed after the bladder and bowel have been emptied, to reduce the risk of rupture of the bladder, bowel or uterus [48]. Additionally, pessary may be helpful after repositioning [1, 10, 19, 90]. Colonoscopic insufflation of the rectosigmoid at a gestational age of 13–15 weeks helped the reposition of the incarcerated uterus, which was reported by Seubert et al. [55]. It has been reported that the epidural anesthesia is an effective way to manage reduction of an incarcerated uterus [54]. In our literature review, six cases ended in a normal pregnancy after reposition under anesthesia [1, 27, 43, 83, 91, 92]. Anesthesia may increase the chance of a successful reduction because the uterus was easily released under anesthesia. If all interventions fail, laparoscopy or laparotomy is usually performed [66]. Operative procedures are not appropriate for patients with uterine incarceration, which is diagnosed before 20 weeks of gestation, because they can result in abortion or preterm delivery; furthermore, following such procedures, close follow-up is needed during the remainder of pregnancy. In the third trimester, uterine contractions usually fail to dilate the cervix because of incarceration. As a result, the risk of uterine rupture should be considered [85]. Caesarean section should be planned if reduction cannot be performed during the remainder of pregnancy [70, 78].

In 162 reviewed cases, cases of incarceration recognized in the first or second trimester of pregnancy account for 67.28% (109/162). Treatment of reposition was successfully attempted in 83 cases. After reposition, 68 patients successfully delivered infants [2, 15, 16, 19, 21, 23, 25, 27, 28, 36, 37, 41, 43, 44, 48, 50, 55, 62, 63, 66, 76, 77, 82, 83, 85, 88‐92, 95, 98‐101], including 36 term deliveries [16, 19, 21, 27, 28, 35, 37, 41, 43, 44, 48, 50, 62, 66, 76, 77, 87, 91, 98, 100, 101], and information for other cases was not available. Treatment methods vary in invasiveness, and because incarceration was quite rare, no study has yet been performed to determine the supremacy of any single treatment modality.

In the present case, the patient achieved correction from incarceration, which was presumed to be related to pelvic adhesions at 16 weeks, by manual manipulation, allowing for an attempt at repositioning. However, it could not be neglected that this patient had a past medical history that involved a high correlation with pelvic adhesions, which could prevent the gravid uterus from normal enlargement and ascent due to possible refractory incarceration. If this patient did not experience relief from incarceration via manual reposition, surgery with laparotomy or laparoscopy might be considered based on the patient’s strong desire to deliver a healthy child.

In conclusion, we report a case of gravid uterine incarceration with a history of lymphatic tuberculosis and IVF-ET. The particular risk factors, including a past history of infection and pregnancy by ART, made our case a relatively specific. As illustrated in the review of similar case reports, gravid uterine incarceration is a rare condition, but serious late gestational complications or poor obstetric outcomes may occur. Early diagnosis is the key to successful treatment. In view of the lack of specific signs or symptoms, additional physical and imaging examinations are critical to early diagnosis of this condition. Appropriate treatment measures that are tailored to the different gestation weeks may improve pregnancy outcomes.