Uterine Inversion

A Life-Threatening Obstetric Emergency

Dawn R. Hostetler, MD, Michael F. Bosworth, DO, Dayton Community Family Practice Residency, Dayton, Ohio.

J Am Board Fam Med. 2000;13(2):120-123. 

In This Article

Discussion

Classification

Uterine inversion is classified not only by the degree of inversion but by the time of onset as well. The uterine fundus that has inverted and lies within the endometrial cavity without extending beyond the external os is called an incomplete inversion. Complete inversion describes an inverted fundus that extends beyond the external os.[4] A prolapsed inversion is one in which the inverted uterine fundus extends beyond the vaginal introitus.[3] A total inversion, usually nonpuerperal and tumor related, results in inversion of the uterus and vaginal wall as well.[4] In terms of onset of the inversion, acute describes the event occurring before cervical ring contraction. If the cervical ring has contracted, a subacute inversion has occurred. The inversion is classified as chronic if 4 weeks have elapsed before the event.[2,4,5,6]

Etiology

Why uterus inversion occurs is unclear. The most likely cause is strong traction on the umbilical cord, particularly when the placenta is in a fundal location, during the third stage of labor.[7] Other factors might include excessive fundal pressure; relaxed uterus, lower uterine segment and cervix; placenta accreta, particularly involving the uterine fundus; short umbilical cord; congenital weakness or anomalies of the uterus; and antepartum use of magnesium sulfate or oxytocin.[5,7,8] Other reports suggest primiparity and rapid emptying of the uterus after prolonged distention as possible predisposing factors. [4,5,6]

Diagnosis

Diagnosis of uterine inversion is usually based on clinical signs and symptoms. When there is complete inversion, the diagnosis is most easily made by palpating the inverted fundus at the cervical os or vaginal introitus, as in the case described above. In incomplete inversion, palpating the fundal wall in the lower uterine segment and cervix might be required for diagnosis. Profuse bleeding, absence of uterine fundus, or an obvious defect of the fundus on abdominal examination, as well as evidence of shock with severe hypotension, will further provide the clinician with diagnostic clues.[5,9]

Although clinical symptoms will provide the diagnosis in most cases, radiographic methods to diagnose inversion have also been described in the literature. Hsieh and Lee[10] describe the sonographic findings of uterine inversion discovered incidentally in an acute incident. In the transverse images was visualized "a hyperechoic mass in the vagina with a central hypoechoic H-shaped cavity." Longitudinal images showed a U-shaped "depressed longitudinal groove from the uterine fundus to the center of the inverted part." Magnetic resonance imaging (MRI) of inversion has also been reported. The appearance of the uterus is similar to that found in sonographic imaging; however, MRI findings are much more conspicuous.[3] Thus radiographic imaging can help when the diagnosis is uncertain after examination, and the patient is sufficiently stable clinically to undergo such evaluation.

Treatment

Treatment of uterine inversion consists of manual manipulation of the uterus and pharmacologic agents to assist in uterine relaxation for correction. Further agents are then given to cause uterine contraction to prevent reinversion and to decrease blood loss. If these methods fail, surgical intervention might be necessary.

Once inversion is recognized, all oxytocic agents should be withheld until correction has been established. Manual correction of inversion through the vagina, known as the Johnson maneuver, consists of pushing the inverted fundus through the cervical ring with pressure directed toward the umbilicus.[8] Controversy exists about whether the placenta should be removed before repositioning the uterus. It is commonly suggested that removal of the placenta before correction will result in increased blood loss and worsening hemodynamics.[2,8]

To assist the clinician in maneuvering the uterus, myometrial relaxation is implemented by various medications. Most commonly used is magnesium sulfate or terbutaline, because they are readily available on most obstetric floors. These medications will not only relax the uterus but will also relax a cervical contraction ring. Reports on the use of intravenous nitroglycerin for uterine relaxation also exist. Benefits cited for the use of low-dose nitroglycerin include quicker onset of uterine relaxation; quick dissipation of the effect, obviating the need for reversal; and less effect on hemodynamics than magnesium sulfate.[11] In the event that correction is not established with tocolytic agents, general anesthesia with halothane may be induced to provide uterine relaxation. This approach can be particularly useful when the patient is hemodynamically unstable, because halothane anesthesia has fewer potential adverse effects on hemodynamics than do the ß-adrenergic tocolytics.[9]

Hydrostatic pressure, cited commonly in the British literature, is another method used to reposition the uterus when inversion has occurred. In this method, first described by O'Sullivan in the British Medical Journal in 1945, a bag of warmed fluid is hung on a pole used for intravenous fluids above the level of the patient and allowed to flow, via tubing, into the vagina. The pressure of the water, held in place by the clinician's hands, results in correction of the inversion. Momani and Hassan[2] reported successful correction in five cases of inversion within a 7-year period using this method. More recently, Ogueh and Ayida[12] described a new technique of hydrostatic pressure. Citing difficulty in maintaining an adequate water seal to generate the pressure required, the authors suggest attaching the intravenous tubing to a silicone cup used in vacuum extraction. By placing the cup within the vagina, an excellent seal is created, and adequate hydrostatic pressure for inversion correction is thus produced. Although success with this technique is cited in the literature, there has been no discussion of the theoretical risk of air or amniotic fluid embolus.

When all attempts at manual reduction of the inversion are unsuccessful, surgical correction might be necessary. Although several procedures have been described, the two most commonly cited are the Huntington and Haultaim procedures. The Huntington procedure requires a laparotomy to locate the cup of the uterus formed by the inversion. Clamps are placed in the cup of the inversion below the cervical ring, and gentle upward traction is applied. Repeated clamping and traction continues until the inversion is corrected. In the Haultaim procedure, an incision is made in the posterior portion of the inversion ring, again through the abdomen, to increase the size of the ring and allow repositioning of the uterus.[9]

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