Two Cases of Heterotopic Cesarean Scar Pregnancy managed at a Tertiary University Center in Austria: A Case Report

Cesarean scar pregnancy (CSP) is a special type of ectopic pregnancy in which the gestational sac implants into the myometrial defect of a previous cesarean section [1]. Numbers have been rising in parallel with increasing cesarean section rates and the frequent use of assisted reproductive technologies, leading to reported incidences between 1:1800 and 1:2500 pregnancies [2].

A heterotopic pregnancy – defined as the coexistence of an intrauterine pregnancy and an ectopic one – is significantly less common, with a prevalence of approximately 1 in 30000 in spontaneous conceptions, although much higher incidences have been reported following assisted reproductive technologies [3]. A heterotopic cesarean scar pregnancy (HCSP) is extremely rare but carries a high risk of severe maternal morbidity. Potential complications include uterine rupture, massive peri- or postpartum hemorrhage, placenta accreta spectrum, and preterm delivery, particularly when trophoblastic tissue invades deep into the myometrium [4]. Presentation at early stages may include mild or nonspecific symptoms such as vaginal bleeding or abdominal pain [3]. However, several reports have documented severe early complications, including first-trimester uterine rupture with expulsion of the ectopic fetus and hemoperitoneum underlining the importance of timely diagnosis and management [5].

Several treatment strategies for HCSP have been reported, including local or systemic methotrexate (MTX), selective embryo aspiration from the cesarean scar, minimally invasive tissue removal, and expectant management [4] [6] [7]. However, systemic MTX administration should be avoided in the presence of a viable intrauterine pregnancy, while embryo aspiration carries an increased risk of hemorrhage or the development of arteriovenous malformations (AVMs), and expectant management is associated with uterine rupture and placenta accreta spectrum. Therefore, selective reduction of the scar pregnancy by transvaginal ultrasound-guided injection of potassium chloride (KCl) has emerged as a preferred minimally invasive option when preservation of the intrauterine pregnancy is intended. Salomon et al. first reported this technique in an HCSP case, achieving successful fetal reduction of the ectopic cesarean scar pregnancy and an uncomplicated delivery of the remaining fetus at 36 weeks [8]. Subsequent reports have confirmed the safety and effectiveness of this approach, although residual placental vascularization may persist for weeks or months and requires close follow-up due to possible risks such as PPROM or bleeding and therefore preterm delivery [6] [9] [10]. More recent cases have shown that residual gestational tissue after selective reduction may evolve into arteriovenous malformations that might require further interventions, such as embolization, advanced hemostatic measures, or hysterectomy [11]. Although KCl instillation is generally considered a safe treatment option, complications including septic abortion have been reported, emphasizing the need for individualized management and careful monitoring [12].

Herein we present two cases of HCSP managed at our institution:

Publication History

Article published online:
09 February 2026

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