Discussion
Uterine rupture is a serious obstetric complication associated with high perinatal and maternal morbidity and mortality (2). In a Norwegian study, complete rupture was associated with 15 % perinatal mortality, while 23 % of infants required transfer to a neonatal intensive care unit, and 6.1 % developed hypoxic ischaemic encephalopathy (3). In the Nordic countries, the incidence of complete rupture is 5.6 per 10 000 births. Among women with a history of caesarean section, the incidence increases to 5 per 1 000 births (4). The main risk factors for uterine rupture are previous uterine surgery, and induction of labour. The combined use of prostaglandins and oxytocin for induction is in particular associated with increased risk (5, 6).
Our patient had previously undergone salpingectomy, and labour was induced with misoprostol – a prostaglandin – post-term. She had the most common symptoms of uterine rupture, which include pain that does not ease between contractions, and pathological cardiotocography. However, uterine rupture was not initially suspected as it is very rare in nulliparous women. Other symptoms may include sudden cessation of contractions, vaginal bleeding, disappearance of the presenting part of the fetus during vaginal examination, peritoneal irritation, a fall in blood pressure, shock or death (7). If uterine rupture is suspected, immediate delivery of both child and placenta are required, most often via a laparotomy.
The surgical notes from the salpingectomy were obtained postpartum. These described a highly proximal, bluish dilation of the fallopian tube, consistent with an interstitial ectopic pregnancy. Interstitial ectopic pregnancies are localised in the proximal part of the fallopian tube, in the muscular region of the uterine wall. Such pregnancies account for 2–4 % of all tubal pregnancies (8), and are most often managed surgically with cornual resection (9). In our patient, intramyometrial vasopressin was administered in the vicinity of the tubal corner to achieve haemostasis, and the wound was sutured at the tubal corner. The right fallopian tube was then removed, but cornual wedge excision was not performed.
Laparoscopy is preferred for surgical procedures on the uterus or adnexa, and uterine rupture is a known, albeit very rare, potential complication, especially after laparoscopic myomectomy (10). Few studies have described the risk of uterine rupture after laparoscopic salpingectomy. Nevertheless, several case reports and retrospective studies have described a risk of rupture in subsequent pregnancies following primary surgical management of an interstitial pregnancy, especially following cornual wedge excision (5, 11). A Norwegian study from 2019 included 33 patients with a history of cornual wedge excision for interstitial pregnancy (12). The control group consisted of patients who had undergone laparoscopic salpingectomy for non-interstitial ectopic pregnancies. The study examined the mode of delivery and the risk of uterine rupture, and found two cases of uterine rupture among the 33 women. For subsequent births, 60 % of the women with a history of cornual wedge excision were delivered by caesarean section, compared with 18 % in the control group (12). Given the sparsity of research in this field, consequences for later pregnancies remain unclear, and thus it is difficult to make recommendations.
In our patient, the combination of a previous surgical intervention and the induction of labour is likely to have contributed to the uterine rupture. On the basis of current knowledge, an ectopic pregnancy in the uterine horn should not necessarily lead to a recommendation for a planned caesarean section, but one should be aware of uterine rupture as a potential complication, especially if labour is induced. This case report also illustrates the importance of obtaining medical records from previous hospital admissions in order to obtain a complete medical history. In the current case, this might have led to a decision not to induce labour, and timely diagnosis and delivery.
The woman has been informed of the possible reasons for her uterine rupture and has been advised to undergo a caesarean section for any subsequent pregnancies.