Background

A ruptured uterus is a catastrophic complication that can lead to severe maternal and fetal morbidity if not diagnosed in time. Common causes of uterine rupture include prior caesarean (8.9 and 37.1 per 10,000 births) (Miller et al. 1997), prior myomectomy, uterine malformations, connective tissue disorders, and placental disorders such as placenta percreta. Rupture of the uterus in the antenatal period prior to labour is a rare event, especially in an unscarred uterus. Uterine rupture in an unscarred uterus is as rare as 0.6 per 10,000 deliveries (Spencer and Robarts 2008).

Our case highlights an unprovoked uterine rupture in a primigravida with an IVF (in vitro fertilization) pregnancy at 32 weeks having a transverse lie and anterior placenta praevia. She had adenomyosis and a past history of laparoscopic treatment of severe endometriosis. Since this patient was not in labour and had an unscarred uterus, this was a rare complication encountered.

Case presentation

A primigravida with an IVF pregnancy following laparoscopic treatment of grade 4 endometriosis, presented at 32 weeks of gestation with an insidious onset of left upper quadrant abdominal pain for one and a half days. An antenatal ultrasound showed an anterior placenta praevia covering the cervical os with the fetus in a transverse lie and normal fetal growth.

On admission, she complained of severe continuous abdominal pain with a single episode of minimal vaginal bleeding. On examination, she had stable vitals, and mild pallor but generalized abdominal tenderness of rapidly increasing severity. There were no uterine contractions and a speculum examination showed a closed cervical os with no vaginal bleeding, which showed that the patient was not in labour. A Cardiotocograph (CTG) was done concomitantly, which showed fetal tachycardia, poor beat-to-beat variability, and atypical variable decelerations, suggestive of non-reassuring fetal status.

In view of the abnormal CTG, an emergency Caesarean section was done immediately on the suspicion of a concealed abruption. At caesarean, on entering the abdominal cavity via a transverse incision, 2 L of blood was found in the peritoneal cavity. A transverse lower segment incision was made on the uterus through the placenta to deliver the baby in a transverse lie by the internal podalic version. The uterus was delivered out of the abdomen to reveal a large rupture on the left side of the fundus, close to the cornu. The rupture was repaired in 3 layers with continuous sutures of Polyglactin 1.

She was transferred to ICU as she quickly became hemodynamically unstable during surgery, requiring 4 units of packed red blood cells and fresh frozen plasma. The baby was transferred in good condition to the neonatal care unit and in due course made an uneventful recovery. Following stabilization, the patient had an uncomplicated postoperative period and was discharged in stable condition. She was advised against further pregnancies (Figs. 1 and 2).

Fig. 1
figure 1

Abnormal CTG with fetal tachycardia and unprovoked fetal decelerations

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Fig. 2
figure 2

Intraoperative image showing cornual rupture

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Discussions

Early detection of uterine rupture and prompt laparotomy are essential in reducing maternal and perinatal morbidity. The classic clinical picture of acute abdomen, hypovolemia, vaginal bleeding, and foetal distress may not always be accompanying symptom. Therefore, regardless of parity, it's crucial to maintain a high index of suspicion for uterine rupture in women presenting with any of the above symptoms. Less common conditions that may present with a similar spectrum of symptoms include subcapsular liver hematoma with or without rupture, rupture of the broad ligament, splenic rupture, uterine torsion, and uterine vein rupture. These conditions need prompt surgical exploration as they cause quick hemodynamic instability; therefore, a high level of clinical suspicion is always needed when above-mentioned symptoms occur in a non-laboring patient.

Our patient, a primigravida at 32 weeks, presented with continuous abdominal pain and fetal distress—symptoms consistent with concealed placental abruption. However, on performing an emergency caesarean, a cornual rupture in the uterus was identified, a rare event in a primigravid unscarred uterus. Early recourse to surgery, led to an optimal maternal and fetal outcome. It has been noted that rupture of an unscarred uterus is a more catastrophic event than rupture through a previous scar, as the area of rupture is more vascular (Miller et al. 1997).

It is important that we discuss that our patient had a history of primary subfertility with grade 4 endometriosis and adenomyosis. She underwent an uncomplicated laparoscopic resection of an ovarian endometrioma and pelvic adhesiolysis for grade 4 endometriosis, a year prior to her IVF. Literature suggests surgical treatment of severe endometriosis, such as deeply infiltrating endometriosis [DIE], has shown a causal relationship with uterine rupture (Ziadeh 2020; Fettback et al. 2015; Leone Roberti Maggiore et al. 2017; Vystavěl et al. 2018). This relationship of DIE with uterine rupture may be explained by a lack of a consensus regarding the depth of excision of tissues and decreased vascularisation of the uterine tissue following extensive bipolar coagulation required in these surgeries.

Our patient also had another risk factor of adenomyosis. There are case reports in the literature of spontaneous uterine rupture of an unscarred uterus caused by adenomyosis in the early third trimester (Vimercati et al. 2022). Alteration in organization and resistance of uterine fibers in adenomyosis may have a contributing role in this pathology (Nikolaou et al. 2013).

Conclusion

Our case demonstrates the potential of a primigravid unscarred uterus to rupture, even if not in labour. It is extremely important to keep this differential diagnosis in mind when a non-labouring primigravida presents with pain abdomen and is diagnosed with abnormal CTG.

Also, we have reviewed the literature where a causal relationship between laparoscopic treatment of severe endometriosis and adenomyosis with uterine rupture has been explored.