What Causes Bleeding Outside of Menstruation?

The causes of intermenstrual bleeding are highly complex—this type of abnormal vaginal bleeding necessitates abstaining from sexual intercourse during the bleeding period, as intercourse may exacerbate vaginal infection. It is essential to identify the precise underlying cause. Endometrial polyps are among the most common contributors to such irregular bleeding; therefore, early diagnosis and treatment are crucial.

What Causes Intermenstrual Bleeding?

1. There are numerous potential causes of intermenstrual bleeding. Such bleeding is inherently abnormal and falls into several categories. After excluding pregnancy, one common cause is menstrual irregularity, which is relatively frequent and often requires no specific intervention. Another common cause is endometrial polyps, which can also lead to intermenstrual bleeding. Diagnosis is typically confirmed via transvaginal ultrasound, and treatment may involve hysteroscopic polypectomy. Additionally, intermenstrual bleeding is frequently observed in women who have undergone cesarean delivery.
　　2. Following cesarean delivery, a cesarean scar defect (also termed “cesarean scar憩室”) may develop at the uterine incision site, resulting in intermenstrual bleeding. This condition is treatable, with management strategies differing based on future fertility plans. For women desiring subsequent pregnancy, surgical correction is more complex: because the scar defect is often large and the overlying myometrium extremely thin (indicating incomplete healing of the uterine incision), the defective tissue must be excised and the uterine wall meticulously re-sutured. Only after complete healing should conception be attempted; otherwise, the risk of uterine rupture during a subsequent pregnancy is significantly increased. In contrast, for women with no further childbearing intentions, hysteroscopic surgery alone usually resolves the intermenstrual bleeding effectively.

3. If vaginal bleeding occurs during the ovulatory phase and no sexual intercourse has taken place recently, it may represent ovulation bleeding—caused by transient estrogen withdrawal leading to partial endometrial shedding. Conversely, if bleeding follows sexual intercourse, it is likely contact bleeding attributable to cervical ectropion (formerly termed “cervical erosion”), cervical polyps, cervical intraepithelial neoplasia (CIN), or even cervical cancer. Bleeding occurring after emergency contraceptive use is typically withdrawal bleeding induced by hormonal disruption. Finally, prolonged anovulation may result in anovulatory dysfunctional uterine bleeding (DUB).

The above outlines the major etiologies of intermenstrual bleeding. We hope this information is helpful to you.