An unusual obstetric event: Postpartum uterine inversion

A 25-year-old woman with a prolonged third stage of labour underwent ventouse-assisted delivery. The placenta was delivered by controlled cord traction, following which postpartum haemorrhage was encountered. After its management, she was shifted to the recovery ward for observation. On day four, she had decreased urine output with bleeding per vaginum.

Based on the clinical profile, the possibility of a uterine inversion was raised. An ultrasound was requested since the patient was haemodynamically stable. On a transabdominal scan, the uterine fundus was projecting into the endometrial cavity. In longitudinal sections, there was the fallen fundus sign, in which the uterine fundus is upside-down (Figure 1). On the transverse sections, there was a bull’s eye or target-like appearance (Figure 2). On MRI, the uterus was seen upside down with the fundus and the adnexal vessels in the vagina. The ovaries and adnexa were drawn centrally towards the cervix (Figures 3 and 4). Imaging confirmed an incomplete uterine inversion. She was successfully managed by surgical means.

Uterine inversion is a rare cause of primary postpartum haemorrhage [2], accounting for 1 in 2000 to 1 in 23,000 deliveries [3]. In uterine inversion, the fundus projects through the endometrial cavity and cervix, with a resultant “inside out” uterus. It may occur either post-delivery or spontaneously. Spontaneous uterine inversions account for 5% of the cases of uterine inversions [3]. It occurs due to the exteriorisation of uterine cavity tumours. Purpureal inversions relate to excessive cord traction in the third stage of labour. Other risk factors include foetal macrosomia, stress on the umbilical cord, placenta accreta, fundal pressure, ligament laxity, a short umbilical cord, and congenital uterine abnormalities [4]. The presence of postpartum haemorrhage with a non-palpable uterine fundus is usually pathognomonic for the condition [4]. On clinical examination, the most common finding is monitoring the uterine fundus beyond the vaginal introitus or its palpation via the external os. Puerperal uterine inversions can be classified as acute, subacute, or chronic based on the timing of their occurrence and the contraction of the cervical ring [5].

Although uterine inversion is a clinical diagnosis, imaging plays an important role when the inversion is incomplete, and when the patient is haemodynamically stable. Imaging helps in grading the degree of uterine inversion: the fundus is within the cavity (first degree), extending till the external os (second degree), beyond the os (third degree), or beyond the introitus (fourth degree) [1,4,5]. On longitudinal sections, ultrasound shows the uterine fundus within the endometrial cavity (fallen fundus sign). On transverse sections, there is a target or bull’s eye appearance of the inverted fundus due to the alternating hyper and hypoechoic uterine layers. The endometrial cavity is not well delineated. MRI depicts the loss of the normal convex contour of the uterus with a U-shaped appearance on sagittal images [1]. On transverse sections, a target appearance may be seen [1]. MRI helps in evaluating the cause of inversion (submucosal fibroids and myometrial masses).

The manual replacement of the uterus (Johnson manoeuvre) is the initial management approach. Due to involution, a rigid ring forms at the cervix, making it difficult to restore the position of the uterus. Uterus-relaxant drugs may be used. When the initial approach fails, surgical techniques are employed (Huntington technique, Haultain technique, or Spinelli’s technique) [4]. When manual reduction fails some authors suggest the use of hydrostatic reduction [6].