Adenomyosis Complicated With Uterine Rupture During Pregnancy

Introduction Uterine rupture (UR) during pregnancy refers to a disruption of the uterine wall involving the myometrium and serosa that occurs in association with pregnancy. The global incidence of UR is rising, and this condition can lead to severe adverse outcomes, including massive hemorrhage, hysterectomy, fetal distress, neonatal cerebral palsy, and even maternal and fetal death.1 Adenomyosis is a benign gynecologic condition characterized by the presence of endometrial glands and stroma within the myometrium, resulting in localized or diffuse lesions. It often manifests as dysmenorrhea, menorrhagia, and infertility, and can substantially affect the patient’s quality of life. Adenomyosis has been associated with an increased risk of pregnancy complications such as infertility, miscarriage, and preterm birth. However, uterine rupture during pregnancy secondary to adenomyosis is extremely rare. Here, we report the clinical course, diagnosis, and management of a pregnant woman with adenomyosis who developed uterine rupture in the second trimester, aiming to provide insight for early recognition and timely management of this rare but life-threatening complication. Written informed consent has been received for the publication. Case presentation A 36-year-old woman, gravida 1, para 0, conceived via in vitro fertilization and embryo transfer, during which two embryos were transferred and one survived. Her medical history included ovarian endometriotic cyst aspiration, diagnostic hysteroscopy, and a previous diagnosis of uterine adenomyosis. At 18+3 weeks of gestation, the patient presented with lower abdominal pain lasting three days. The pain was intermittent, cramping in nature, and initially mild but became progressively severe, accompanied by nausea, vomiting, and fatigue. Physical examination revealed generalized abdominal tenderness with rebound pain. Emergency abdominal ultrasound showed an uneven hypoechoic area in the hepatorenal space suggestive of hemoperitoneum, likely due to uterine rupture with bleeding. Emergency exploratory laparotomy was performed. A cesarean section was carried out to remove a stillborn fetus. The placenta could not be separated spontaneously and was found to be extensively adherent to the uterine myometrium. Examination of the posterior uterine wall revealed inflammatory exudates throughout the lower segment, with a transverse rupture (~4 cm) on the right side involving the serosa and partial myometrium, and an oblique rupture (~3 cm) on the left side that did not penetrate into the uterine cavity. The ruptured tissue was thickened, firm, and friable, with active bleeding. Histopathological examination revealed fragmented smooth muscle and decidual tissue with hemorrhage, degeneration, and neutrophil infiltration in the posterior wall, consistent with adenomyosis. The patient recovered well postoperatively and was discharged after follow-up confirmed clinical stability. Discussion Uterine rupture is a rare but catastrophic obstetric emergency, most commonly occurring in late pregnancy or during labor. The global incidence ranges from 0.016% to 0.30%.2 Adenomyosis, a common condition among women of reproductive age, has been increasingly recognized as a factor potentially associated with pregnancy complication.3 However, uterine rupture caused by adenomyosis remains exceptionally uncommon and poses diagnostic and therapeutic challenges. To date, only a limited number of cases have been reported. Nikolaou et al.4 described 12 cases of adenomyosis-related uterine rupture during pregnancy, highlighting the heterogeneous clinical presentation and diagnostic difficulty. Our case adds to the limited evidence base, emphasizing the need for clinical vigilance. The exact mechanism by which adenomyosis contributes to uterine rupture during pregnancy remains unclear. Several possible mechanisms have been proposed: Endometrial–myometrial interface disruption: damage to the basal layer of the endometrium and invasion of ectopic endometrial tissue into the myometrium can lead to chronic inflammation, fibrosis, and reduced tensile strength of the uterine wall. Inflammatory and oxidative stress environment: ectopic endometrial glands secrete inflammatory mediators and enzymes such as superoxide dismutase, nitric oxide synthase, and catalase, generating reactive oxygen species that promote tissue degeneration and fibrosis.5,6 Reduced myometrial elasticity: the proliferation and hypertrophy of surrounding smooth muscle fibers in adenomyotic foci cause diffuse uterine enlargement and decreased elasticity. During mid- to late pregnancy, as intrauterine pressure rises, these weakened regions may fail under tension, leading to rupture.7 Abnormal placental implantation: adenomyosis may predispose to abnormal trophoblast invasion and placenta accreta spectrum disorders by disrupting the normal endometrial–myometrial junction. In our case, placental adhesion and partial implantation were found intraoperatively, further weakening the uterine wall. Although the patient also had a history of diagnostic hysteroscopy and mild placental implantation, these factors alone were insufficient to explain the rupture. Given that the rupture sites corresponded to areas of adenomyotic thickening rather than the placental bed, and histopathology confirmed adenomyosis in the rupture region, adenomyosis was considered the major contributing factor in this case (Supplementary Table 1, https://links.lww.com/MFM/A111). Diagnosing uterine rupture during pregnancy is challenging due to its nonspecific symptoms and limited imaging sensitivity. Ultrasonography has low sensitivity in detecting threatened rupture, and diagnosis relies heavily on clinical suspicion. For pregnant women with adenomyosis who experience unexplained abdominal pain, especially during the second or third trimester, clinicians should maintain a high index of suspicion for possible uterine rupture. Management requires immediate surgical intervention to control bleeding and repair or remove the uterus, depending on the extent of damage and the patient’s condition. Intraoperative measures should ensure hemostasis and preservation of life. Postoperatively, close monitoring and psychological support are essential, as patients may experience significant emotional distress after such obstetric emergencies. Conclusion Uterine rupture secondary to adenomyosis during pregnancy is exceedingly rare but potentially fatal. This case underscores the importance of early recognition and timely surgical management. For pregnant women with adenomyosis and unexplained abdominal pain, uterine rupture should be considered in the differential diagnosis. Further studies are needed to elucidate the underlying mechanisms and to establish preventive and management strategies for this high-risk population.