Ultrasonographic diagnosis of incomplete uterine inversion

Puerperal uterine inversion is a rare (1/3127 births), unpredictable and potentially fatal obstetric emergency in which the uterine fundus collapses into the uterine cavity at the time of placental delivery1. In severe cases the fundus can prolapse through the cervix and out through the vagina. Although the underlying risk factors for uterine inversion are not fully understood, it has been postulated that it is caused by mismanagement of the third stage of labor in some cases in which the placenta is implanted in the fundus, when strong umbilical-cord traction and fundal pressure have been applied before placental separation2–4. Uterine inversion can lead to major postpartum hemorrhage5, and associated high maternal mortality, unless the condition is recognized and corrected quickly. Four degrees of uterine inversion may be described according to the stage of uterine exteriorization4,6: first degree (incomplete inversion), in which the inverted fundus extends to, but not through the cervix; second degree, in which the fundus extends through the cervix but remains within the vagina; third degree, in which the fundus extends beyond the vagina; and total inversion, in which the vagina and uterus are inverted. We report a case of puerperal incomplete uterine inversion diagnosed by three-dimensional ultrasound (3DUS) examination. A healthy 35-year-old woman came to our labor department in spontaneous labor at 40 weeks’ gestation. She had undergone a previous Cesarean section 4 years earlier, which was performed because of fetal malpresentation. In the current pregnancy, an infant weighing 4015 g was delivered using ventouse and forceps, with Apgar scores of 7 and 9 at 1 and 5 min, respectively. A succenturiate placenta was expelled late but spontaneously. Following this there was heavy bleeding, and intravenous fluid replacement and uterine cavity curettage were performed. Curettage was difficult because of the presence of what was suspected to be a myoma, and no retained products of conception were obtained. The patient became anemic and was transfused with four units of packed red cells. Ultrasound examination was performed 20 h after delivery, using a GE Voluson 730 (GE Medical Systems, Milwaukee, WI, USA), because of mild but persistent bleeding. The images obtained were strongly suggestive of incomplete uterine inversion (Figure 1). An estimation of the volume of the inverted part was then performed using VOCAL TM (Virtual Organ Computer-aided AnaLysis) (Figure 2). The woman underwent a laparotomy and the sonographic diagnosis was confirmed. Furthermore, a small uterine rupture in the right third of the previous Cesarean section scar was identified. Although the inverted uterus was successfully repositioned manually, manipulation was very difficult owing to the presence of a strong constriction ring, which persisted after administration of uterorelaxants. Tubal sterilization was performed on request. Postoperative recovery was uneventful and the patient was discharged 3 days after surgery. There have been few images published in the literature revealing ultrasound diagnosis of uterine inversion7. Although the diagnosis of uterine inversion is usually made on clinical grounds4, ultrasound assessment might be useful for providing confirmation and may also detect cases that are not clinically apparent, such as that described here. Careful evaluation is imperative, and in our case the correct diagnosis was only possible after ultrasound examination. 3DUS imaging with orthogonal planes showed the inverted fundus inside the uterine cavity, and the constriction ring. The suspected myoma found on curettage was revealed to be the inverted uterine fundus. Prompt diagnosis of uterine inversion and immediate treatment are necessary because it can cause lifethreatening hemorrhage. Thus, minimizing the length of time from diagnosis to clinical/surgical correction (uterine replacement) and resuscitation management (intravenous fluid replacement and blood transfusion) are important for a successful prognosis8. In conclusion, ultrasound evaluation facilitates the assessment of clinically undetectable uterine inversion and should always be performed as soon as possible in cases of unexplained postpartum hemorrhage. This will usually serve to confirm or exclude the presence of retained products of conception, but may also detect cases of uterine inversion such as that presented here.