Annals of B Pod: Uterine Incarceration
/HISTORY OF PRESENT ILLNESS
Patient is a G3P2 female in her 20s at 12 weeks gestational age (wGA), presenting with urinary retention. She reports that for the past two weeks she has had to strain to urinate. She was seen by her midwife provider for evaluation of this issue several days ago, at which time she underwent an ultrasound that was suggestive of uterine incarceration. She was scheduled for follow-up with her obstetrician in several days and cautioned to report to the emergency department (ED) if unable to urinate. This morning, she was only able to urinate several drops. She also developed progressively worsening pain and pressure in her suprapubic abdomen. She denies hematuria, dysuria, vaginal bleeding, fevers, chills, nausea, and vomiting. Of note, the patient’s previous two pregnancies were full term, uncomplicated, and ended in spontaneous vaginal deliveries.
PAST MEDICAL HISTORY: Anemia, anxiety
Past surgical history: none relevant
Medications: Prenatal vitamins, Sertraline
Allergies: None
Physical exam
Vitals: HR 87, BP 121/73, RR 21, SpO2 100% ORA, T 98.7F
Examination reveals a well-appearing woman reclining on the hospital bed, in no acute distress. She is breathing comfortably on room air, with strong distal pulses and well-perfused extremities. Her abdominal exam shows a gravid uterus that is nontender with a firmly distended suprapubic abdomen that is tender to palpation. On pelvic exam there was normal vaginal epithelium with no blood in the vaginal canal, a cervix that was unable to be visualized, and bulging of the posterior fornix.
Notable diagnostics
CBC: unremarkable, BMP: unremarkable
Quantitative hCG: 117,539
Figure 1: Transabdominal POCUS imaging demonstrating transverse (A) and longitudinal (B) views of a retroverted uterus with an IUP and no free intraabdominal fluid.
Urinalysis: negative for blood, nitrites, and leukocytes, many bacteria, and moderate budding yeast
Transabdominal point-of-care ultrasound (POCUS): Transverse and longitudinal images demonstrating a retroverted uterus with no free fluid seen in the cul-de-sac and an intrauterine pregnancy (IUP) (Figure 1).
Hospital Course
Shortly after the patient’s arrival, a Foley catheter was placed with return of significant urine and subsequent resolution of abdominal pain. Obstetrics (OB) was consulted due to previously reported concerns of uterine incarceration and presentation of urinary retention. They agreed with the diagnosis of uterine incarceration and attempted manual reduction at bedside. Despite multiple doses of oxycodone, this procedure proved too painful for the patient to undergo while conscious in the emergency department and she was subsequently transferred to the OB floor.
Using a pelvic bed and intravenous Dilaudid for pain control, the OB team was able to manually reduce the patient’s uterus. Subsequent transabdominal ultrasound imaging confirmed appropriate uterine placement and the patient was able to void spontaneously following foley removal. She was then discharged home. She continued to receive routine prenatal care with her outpatient OB providers without further complication.
Discussion
Pathophysiology and Epidemiology
Figure 2: Illustrative diagram of the anatomic differences between normal uterine growth (A) and uterine incarceration (B). Illustration by Olivia Gobble, MD.
Uterine incarceration is a rare and potentially devastating pregnancy complication in which the gravid uterus becomes trapped in the posterior pelvis. This pathology requires the preexistence of uterine retroversion, which is found in approximately 15% of normal pregnancies. [1] This normal variant typically resolves as the pregnancy progresses (usually between 12- and 14-wGA), with the uterus growing out of the pelvis and spontaneously anteverting in the abdominal cavity. [2] However, in a small subset of cases, the retroverted uterus remains lodged between the pubic symphysis and sacrum, as demonstrated in Figure 2. This occurs with an estimated incidence of 1 in 3000 pregnancies. [3] As the pregnancy progresses and the uterus grows, the cervix is pushed against the pubic symphysis and bladder trigone, and the uterine corpus exerts pressure against the sacrum and rectum.
Clinical Presentation
The increasing pressure exerted by the growing uterus is responsible for the classic symptoms of uterine incarceration: urinary manifestations (including urinary retention, paradoxical incontinence, dysuria, increased urinary frequency, and increased urinary urgency) which are present in 53.7% of cases; abdominal pain (35.8%); constipation (6.79%); vaginal bleeding (6.17%); pelvic pain (6.79%); back pain (4.94%); and tenesmus (1.85%). [2] Uterine incarceration is typically diagnosed in the second trimester as the uterus has to reach sufficient size to cause these symptoms. Any condition that limits the movement of the uterus, whether by increased size, tethering within the abdominal cavity, or abnormal shape, is a risk factor for uterine incarceration. These conditions include endometriosis, pelvic inflammatory disease, uterine prolapse, pelvic adhesions from abdominal surgery, and uterine abnormalities, including fibroids, tumors, and anomalies such as bicornuate or didelphic uterus. [2]
Evaluation and Diagnosis
Diagnosis of uterine incarceration can be made clinically, although it is increasingly made with either ultrasound or magnetic resonance imaging (MRI). A physical exam consistent with uterine incarceration may include a very anterior or absent cervix on pelvic exam, bulging of the posterior vaginal wall, and a palpable, immovable fundus within the sacral curvature. [2] Ultrasound findings suggestive of incarceration include an anteriorly displaced cervix compressing the urinary bladder, in turn leading to a distended, lengthened bladder full of urine. [4] MRI may show an elongated cervix parallel to the vagina (in normal anatomy, the cervix is perpendicular to the vagina). [4] The sensitivity and specificity of ultrasound compared to MRI have not been thoroughly studied, but Gardner et al. does note that ultrasound may be more likely to confuse uterine incarceration for ectopic pregnancy. [4]
Management and Prognosis
Following diagnosis of uterine incarceration, prompt reduction of the uterus is necessary to prevent complications, which include bladder rupture, kidney injury, renal failure, spontaneous abortion, intrauterine growth restriction (IUGR), uterine ischemia, uterine sacculation, uterine rupture, premature rupture of membranes (PROM), preterm labor (PTL), and vaginal or cervical injury during delivery. [2,4] Reduction can sometimes be achieved by urinary catheterization followed by chest-knee positioning (these two maneuvers increase the space between the pubic symphysis and the sacrum, in turn allowing the uterus to pass through this narrow passageway). If this fails, manual reduction should be attempted. This is performed by inserting two fingers into the vagina and applying upward pressure to the bulging uterine fundus (typically within the posterior fornix), with optional cervical clamping for additional traction. Of note, manual reduction is typically not recommended after 20 weeks’ gestation, due to increased complication rates such as preterm premature rupture of membranes (PPROM) or PTL. [5] Other reduction options, which cannot be performed in the emergency department, include colonoscopy, laparoscopy, and laparotomy. If a pregnant patient carries an incarcerated pregnancy to delivery, they should undergo Cesarean section. [6]
Summary
Uterine incarceration is a rare diagnosis that presents with nonspecific symptoms. Nevertheless, it is a dangerous obstetric emergency that must remain on the emergency physician’s differential, especially in second-trimester pregnant patients with urinary symptoms. Further evaluation can be performed with ultrasound or MRI, and, after close consultation with OB, manual reduction can be performed at the bedside in the ED.
AUTHORED BY Ann Wolski, MD
Dr. Wolski is a PGY-2 in Emergency Medicine at the University of Cincinnati
EDITING BY DR. Olivia Gobble AND THE ANNALS OF B POD EDITORS
References
1. Fadel HE, Misenhimer HR. Incarceration of the retroverted gravid uterus with sacculation. Obstet Gynecol. 1974;43(1):46-49.
2. Han C, Wang C, Han L, et al. Incarceration of the gravid uterus: a case report and literature review. BMC Pregnancy and Childbirth. 2019;19(1):408.
3. Gibbons JMJ, Paley WB. The Incarcerated Gravid Uterus. Obstetrics & Gynecology. 1969;33(6):842.
4. Gardner CS, Jaffe TA, Hertzberg BS, Javan R, Ho LM. The Incarcerated Uterus: A Review of MRI and Ultrasound Imaging Appearanc- es. American Journal of Roentgenology. 2013;201(1):223-229.
5. Kim HS, Park JE, Kim SY, et al. Incarceration of early gravid uterus with adenomyosis and myoma: Report of two patients managed with uterine reduction. Obstet Gynecol Sci. 2018;61(5):621-625.
6. Ntafam CN, Beutler BD, Harris RD. Incarcerated gravid uterus: A rare but potentially devastating obstetric complication. Radiology Case Reports. 2022;17(5):1583-1586.
