Uterine leiomyomas, or fibroids, are benign smooth muscle tumors occurring in up to 25% (1) of reproductive-aged women. Although most remain asymptomatic during pregnancy, approximately two-third may increase in size during the first trimester, potentially leading to obstetric complications. Reported maternal-fetal complications include recurrent pregnancy loss, preterm labor, placental abruption, malpresentation, obstructed labor, cesarean delivery, and postpartum hemorrhage (PPH). Among the different fibroid types, submucosal fibroids—accounting for about 10–15% (2)—are most likely to interfere with implantation and placentation because of their proximity to the endometrium. While atonic primary PPH is well documented, persistent secondary PPH due to submucosal fibroids is extremely uncommon. This case series presents three illustrative cases of submucosal fibroids leading to persistent secondary PPH, emphasizing diagnostic challenges, pathophysiology, and therapeutic strategies.

Case 1 A 29-year-old woman (G2P1L1, previous cesarean section) presented at 20 weeks’ gestation with vaginal bleeding. Examination revealed mild pallor and uterine size corresponding to 24 weeks. Ultrasound showed a single live intrauterine fetus with nil liquor, a fundal-anterior submucosal fibroid (5 × 6 cm), and a large subchorionic hematoma (8 × 6 cm). In view of fetal demise, medical termination was performed with mifepristone and misoprostol. Initial expulsion was uneventful, but 12 hours later, she developed persistent trickling per vagina. Repeat imaging revealed a large vascular submucosal fibroid with active blood flow. Conservative measures (uterine tamponade, tranexamic acid, and fluids) failed; hemoglobin dropped from 10 g/dL to 7 g/dL within 24 hours. Uterine artery embolization (UAE) demonstrated contrast extravasation into the fibroid, confirming the bleeding source. Hemostasis was achieved post-embolization, and the patient stabilized. Case 2 A 26-year-old primigravida with a posterior submucosal fibroid (6 × 7 cm) was referred for safe confinement. Initially detected at 32 weeks (3 × 4 cm), the fibroid enlarged and became partially covered by placenta by 39 weeks. She had an uneventful vaginal delivery at 40 weeks, with spontaneous placental expulsion and no immediate PPH. On postpartum day 5, she presented with profuse vaginal bleeding and hypovolemic shock (pulse 120 bpm, BP 80/50 mm Hg). Ultrasound showed a vascular posterior submucosal fibroid with no retained products. Despite uterotonics and transfusion, bleeding persisted; peripartum hysterectomy was performed. Histopathology revealed subinvolution of placental bed with dilated bleeding vascular sinuses overlying the fibroid. Case 3 A 32-year-old G3A2 with a fundal submucosal fibroid (4 cm) was monitored for recurrent early pregnancy losses. The fibroid enlarged to 6 cm by 14 weeks and remained stable thereafter. At 39 weeks, due to breech presentation, she underwent elective cesarean delivery. A left lateral submucosal fibroid (6 × 7 cm) with partial placental implantation was noted intraoperatively. Mild intraoperative PPH was controlled with oxytocics. However, on postoperative day 1, she developed persistent bleeding with clots. Ultrasound revealed the same vascular submucosal fibroid, intact scar, and no hematoma. She underwent UAE, achieving complete cessation of bleeding and uterine conservation.

Uterine leiomyomas are the most prevalent benign smooth muscle tumors of the female genital tract, with an estimated incidence of 20–25% among women of reproductive age (2). Their occurrence during pregnancy is relatively uncommon, ranging from 0.3% to 2.6%, but when present, fibroids can complicate gestation and puerperium in diverse ways (3). The clinical behavior of fibroids during pregnancy depends primarily on their location, size, and number. Among the different types, submucosal fibroids—constituting only 10–15% of all uterine fibroids—are most likely to distort the endometrial cavity and interfere with placentation, predisposing to pregnancy loss, placental abnormalities, and postpartum hemorrhage (4). Fibroids during pregnancy have been associated with an increased risk of spontaneous abortion, preterm labor, intrauterine growth restriction, fetal malpresentation, cesarean delivery, and postpartum hemorrhage (5). The degree of risk correlates with fibroid size and proximity to the endometrial surface. Submucosal and intramural fibroids, in particular, distort the uterine cavity and compromise uteroplacental perfusion, leading to decidual necrosis and poor placental attachment. When the placenta implants directly over a fibroid, as observed in all three cases of this series, the physiological remodeling of spiral arteries is hindered, predisposing to placental site subinvolution (PSS) and persistent postpartum bleeding (6-9). Secondary postpartum hemorrhage (PPH)—defined as significant vaginal bleeding between 24 hours and 6 weeks after delivery—is commonly attributed to retained products of conception (RPOC), infection (endometritis), or coagulopathy. However, in rare instances, it may result from submucosal fibroid-associated vascular pathology, particularly placental site subinvolution. During normal involution, the spiral arteries at the placental bed undergo obliteration via trophoblast withdrawal, fibrotic intimal thickening, and thrombotic closure (11). In contrast, in PSS, these arteries remain dilated and incompletely thrombosed, with residual endovascular and intramural trophoblasts maintaining vessel patency. Submucosal fibroids amplify this defect by compressing and distorting the myometrial vasculature, thereby altering the normal postpartum regression of uterine blood vessels (12). Histopathological examination in Case 2 clearly demonstrated dilated vascular sinuses with variably aged thrombi and hyalinized walls, confirming the mechanism of subinvolution-induced persistent PPH. Doppler imaging in Cases 1 and 3 further revealed increased internal vascularity within the fibroid, consistent with ongoing perfusion and active bleeding. Secondary PPH due to submucosal fibroids often presents insidiously, with delayed bleeding days after an apparently normal delivery or abortion, as seen in this series. The uterus may appear well contracted and non-tender, misleading clinicians to suspect infection or RPOC instead. Therefore, high clinical suspicion and prompt imaging are critical (13). Color Doppler ultrasound is the preferred first-line investigation. In all three cases, Doppler demonstrated intense internal vascular flow within the fibroid and absence of retained tissue, enabling a confident diagnosis. Magnetic resonance imaging (MRI) may be used in equivocal cases to delineate the vascular supply and guide interventional planning. Laboratory workup should include complete blood count, coagulation profile, and serum β-hCG (to rule out gestational trophoblastic disease) (14). When secondary PPH persists despite medical management and imaging shows high-velocity intramyometrial flow, uterine artery embolization (UAE) becomes both diagnostic and therapeutic. Management of fibroid-associated PPH requires a stepwise, multidisciplinary strategy involving obstetricians, anesthesiologists, and interventional radiologists. Initial management includes uterotonics (oxytocin, ergometrine, prostaglandins), antifibrinolytics (tranexamic acid), uterine tamponade (Bakri balloon, packing), and aggressive fluid and blood replacement (15). These were attempted in Cases 1 and 3 but proved insufficient due to ongoing vascular leakage from fibroid sinuses. Uterine artery embolization has emerged as a valuable, fertility-preserving alternative in cases where conventional therapy fails. It achieves selective occlusion of bleeding vessels while maintaining overall uterine perfusion. Both Cases 1 and 3 demonstrated complete cessation of bleeding and subsequent reduction in fibroid size post-UAE (16). This underscores UAE’s role as an effective uterus-conserving modality, particularly in young women desiring future fertility. In hemodynamically unstable patients or where embolization is unavailable or fails, hysterectomy remains the definitive option. Case 2 illustrates such a scenario—despite resuscitation and maximal uterotonics, persistent hemorrhage necessitated emergency hysterectomy. Histopathology provided confirmatory evidence of the fibroid as the bleeding source. The findings in this series are consistent with prior reports emphasizing the rare but serious association between submucosal fibroids and secondary PPH. Lee et al. (17) highlighted that fibroid location within the endometrial cavity is a key determinant of pregnancy complications, with submucosal fibroids exerting the greatest adverse effects on placentation and uterine contractility. Vitale et al. (18) noted that fibroids larger than 5 cm are more likely to undergo red degeneration and compromise uterine contractility postpartum, predisposing to hemorrhage. Triantafyllidou et al. (19) described placental site subinvolution as a histopathologic cause of persistent bleeding and hysterectomy in young women which is a finding mirrored in our second case. Although most literature describes primary atonic PPH, persistent delayed hemorrhage secondary to vascular communication over fibroids remains sparsely reported. This series therefore adds to existing evidence by emphasizing Doppler-guided recognition and the successful role of UAE in conservative management. Given the recurrence risk and potential for catastrophic bleeding, pre-pregnancy evaluation of women with known fibroids is crucial. Hysteroscopic submucosal myomectomy is the recommended approach for large (>4–5 cm) or cavity-distorting fibroids before conception. In cases where fibroids are discovered during pregnancy, counseling for delivery in tertiary centers with interventional radiology, blood bank, and surgical support is essential.

Submucosal fibroids, though uncommon, can cause life-threatening secondary postpartum hemorrhage due to placental site subinvolution and persistent vascular channels. Early antenatal identification, vigilant intrapartum monitoring, and access to multidisciplinary care including interventional radiology are vital for optimal outcomes. Uterine artery embolization offers an effective, uterus-preserving alternative, while hysterectomy remains a life-saving last resort. Pre-pregnancy hysteroscopic resection of large submucosal fibroids can significantly reduce maternal morbidity and prevent recurrence.

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