Management of Uterine Decidual Cast
A uterine decidual cast requires supportive care with reassurance and pain management, as it is a self-limited condition that resolves spontaneously once the cast is expelled. 1, 2
What Is a Decidual Cast?
A decidual cast represents spontaneous sloughing of the entire endometrium as a single piece that retains the shape of the uterine cavity. 1 This occurs when progesterone-mediated decidualization of the endometrium fails to undergo normal dissolution, maintaining its structural integrity during passage. 2
Clinical Presentation and Diagnosis
- Patients typically present with severe dysmenorrhea, heavy vaginal bleeding, and passage of tissue per vagina. 1, 3
- The combination of bleeding and obstructive symptoms can mimic genital tract obstruction on imaging, creating diagnostic confusion. 3
- Diagnosis is confirmed by histopathologic examination of the expelled tissue. 1
Essential Workup Before Treatment
- Rule out pregnancy immediately with urine or serum pregnancy testing in all reproductive-age women, as this is the critical first step. 4
- Perform pelvic ultrasound to exclude ectopic pregnancy, retained products of conception, or other structural pathology. 1, 2
- If the cast has not yet passed and imaging shows apparent obstruction, examination under anesthesia may be necessary to identify the cast. 3
Management Algorithm
Acute Phase (During Symptoms)
- Provide NSAIDs for pain management unless contraindicated by cardiovascular disease. 4
- Offer reassurance that symptoms will resolve spontaneously following complete passage of the cast. 1
- No surgical intervention is required in uncomplicated cases. 1
Post-Expulsion Management
- Send expelled tissue for histopathologic confirmation to rule out other pathology, including products of conception or infection. 2
- If the decidual cast occurred secondary to hormonal contraception cessation, counsel the patient about this rare side effect before restarting therapy. 1, 5
- Consider alternative contraceptive methods if the patient finds this side effect unacceptable. 6
Critical Association with Hormonal Contraception
- Decidual casts are strongly associated with progesterone-containing hormonal contraceptives, particularly following poor compliance or cessation of oral contraceptive pills, Depo-Provera injections, or combined use of IUD with oral contraceptives. 1, 2, 7
- The phenomenon occurs because exogenous progesterone induces endometrial decidualization, and abrupt withdrawal or irregular use prevents normal dissolution. 2
- Patient education before initiating progesterone-containing contraceptives should include mention of this rare but dramatic side effect to reduce stress if it occurs. 1, 5
Important Complications to Monitor
- In rare cases, decidual casts can become infected or contain retained products of conception from an unrecognized early pregnancy loss. 2
- If fever, purulent discharge, or signs of infection develop, treat with appropriate antibiotics and consider examination under anesthesia to ensure complete expulsion. 2
- Persistent bleeding or pain after cast passage warrants further evaluation with endometrial biopsy to exclude other pathology. 4
Common Pitfalls to Avoid
- Do not mistake a decidual cast for miscarriage tissue without histopathologic confirmation, as management differs. 2
- Do not perform unnecessary surgical intervention (curettage or hysteroscopy) for uncomplicated decidual cast, as spontaneous passage is the natural course. 1
- Do not restart hormonal contraception immediately without counseling the patient about the association and obtaining informed consent. 5