The term ‘uterine retroversion’ was first mentioned by Hunter in the mid nineteenth century to describe the situation in which the uterine body lies posterior to the longitudinal axis of the cervix. It is now known that this is a normal anatomical variant seen in up to 20 per cent of women. At varying times, uterine retroversion has been held to be responsible for, or implicated in, diverse disorders such as infertility, abortion, dysmenorrhoea, and deep dyspareunia. While all these problems do occur in association with uterine retroversion, it is unusual for the relationship to be causative in the absence of associated gynaecological pathology. However, certain diseases can cause a normally anteverted uterus to be bound down into a position of retroversion in the pouch of Douglas. These include adhesions secondary to pelvic sepsis or surgical trauma and endometriosis. The physiological and pathological varieties of uterine retroversion can usually be distinguished clinically by the degree of uterine mobility and, to a certain extent, by the uterine and adnexal tenderness elicited at bimanual examination.

Between 11 and 19 per cent of conceptions begin in a retroverted uterus. Typically, as the uterus enlarges in the first trimester of pregnancy it adopts an anteverted position and expands out of the pelvis. By 12 to 13 weeks the uterine fundus is palpable just above the symphysis pubis. In a small proportion of women the enlarging retroverted uterus becomes wedged in the hollow of the sacrum, compressing the bladder neck and urethra against the symphysis pubis. This condition, described as incarceration of the retroverted gravid uterus, leads to acute urinary retention and occurs in approximately 1 in 3000 pregnancies. The mechanism of the urinary retention is probably outflow obstruction due to urethral compression, but the interesting suggestion has been made that the impacted uterus may prevent the straightening of the posterior urethrovesical angle during attempted voiding.

Patients, frequently multiparous, present between 13 and 17 weeks' gestation with a history of increasing urinary frequency, hesitancy, and a sensation of residual urine. This may have persisted a few days before developing into acute urinary retention with severe suprapubic pain, urgency, and inability to void. Rectal pressure and tenesmus are sometimes described. On physical examination the patients are not shocked but may be tachycardic due to pain. An abdominal mass can be detected arising from the pelvis and may extend to the umbilicus. It is important to recognize that this mass is the bladder and not the uterus. This is readily apparent on bimanual examination, when the impacted uterus is felt as a soft mass filling the pelvis. The diagnosis is usually obvious, although confusion may be caused by leakage of urine due to overflow incontinence. The diagnosis can be confirmed by ultrasound, but this is rarely necessary. Once the condition is suspected, a urinary catheter should be passed. This will provide immediate symptomatic relief. The volume of urine obtained usually exceeds 500 ml and a volume of up to 2500 ml has been reported. The urine is sterile.

Treatment options include catheterization, either continuous or intermittent, or uterine replacement. If catheterization alone is used, the patient should be encouraged to lie on her stomach, and this can be alternated with the knee–chest position. She may be allowed home with an indwelling catheter for several days. The uterine position often corrects spontaneously, and once this has occurred incarceration is most unlikely to recur. A vaginal pessary, preferably of the Hodge variety, will help to maintain the uterus in a position of anteversion.

A more active technique involves replacing the uterus manually. The bladder is first emptied with a catheter and the bowel evacuated by an enema. The patient is placed in the lithotomy position and bimanual examination performed. Gentle but steady pressure is applied by two fingers in the posterior vaginal fornix and the uterus is displaced upwards until loss of resistance is felt. Usually this manoeuvre can be achieved using analgesics alone, although occasionally an epidural or even a brief general anaesthetic is required. Great care must be taken in this circumstance to avoid the use of excessive pressure, which could damage the fetus or interfere with placental circulation. Once successfully reduced, a Hodge pessary should be fitted to maintain anteversion. Rarely, the uterus may be bound in retroversion by dense pelvic adhesions but, in practice, it is nearly always possible to achieve anteversion without resorting to surgical intervention. It is likely that adhesions of this degree prevent conception, so the situation is avoided. If untreated, incarceration of the uterus may progress to cause ischaemic damage to other pelvic structures. However, it has been known for a pregnancy to progress to term without symptoms or complications in a uterus maintained in a retroverted position, the situation being discovered when a caesarian section was performed.

Not all cases of acute urinary retention towards the end of the first trimester of pregnancy are due to uterine retroversion. Other rare causes include impaction due to uterine fibroids and retention associated with bladder tumours. Several cases of acute urinary retention in the first trimester have also been described with no obvious cause. These idiopathic cases respond to short-term catheterization.

Any disorder causing acute urinary retention in the female may also occur incidentally in pregnancy. In the absence of an impacted, retroverted uterus, urological, neurological, and pharmacological causes should be excluded.

Acute urinary retention due to incarceration of a retroverted gravid uterus occurs in approximately 1 in 3000 pregnancies. Urinary catheterization over several days is usually associated with spontaneous resolution, but the impacted uterus can be replaced bimanually. Once the uterus is normally situated it is very uncommon for retroversion to recur, but a Hodge pessary can be fitted for several weeks to assure that anteversion is maintained. In the absence of a retroverted uterus, other causes for acute urinary retention should be sought.

Francis WJA. Disturbances of bladder function in relation to pregnancy. Br J Obstet Gynaecol 1960; 72: 353.

Hansen J, Asmussen M. Acute urinary retention in the first trimester of pregnancy. Acta Obstet Gynaecol Scand 1985; 64: 279.

Jackson D, Elliott JP, Pearson M. Asymptomatic uterine retroversion at 36 weeks gestation. Obstet Gynecol 1988; 71: 466.

Schwartz Z, Dgani R, Katz Z, Lancet M. Urinary retention caused by impaction of leiomyoma in pregnancy. Acta Obstet Gynaecol Scand 1986; 65: 525.

Silva PD, Berberich W. Retroverted impacted gravid uterus with acute urinary retention. Obstet Gynecol 1986; 68: 121.