What illness is it when there is brown discharge one or two weeks after the end of the menstrual period?

Patient's question:

Patient Age: 18
Detailed Condition and Purpose of Consultation: The menstrual cycle was normal previously, and it has been normal these past few months as well. However, sometimes there is brown discharge (2–4 days) one or two weeks after the end of the period. What could be the cause?

Doctor's answer:

Hello: Based on your description of symptoms, it could be considered ovulation bleeding.
During the mid-cycle, which is the ovulation period, a temporary decline in estrogen levels causes the endometrium to lose hormonal support, leading to partial shedding of the endometrium and resulting in regular vaginal bleeding, known as ovulation bleeding. In traditional Chinese medicine, this is referred to as "intermenstrual bleeding."
Treatment
1. Western medicine treatment: Diethylstilbestrol 0.25–0.5 mg per day, starting 3 days before ovulation and stopping 2–3 days after the bleeding stops.
2. Traditional Chinese medicine treatment: Liuwei Dihuang Wan, Gujing Wan, and Xuefu Zhuyu Wan.
Prevention and Care
1. Pay attention to menstrual and postpartum health care, maintain external genital hygiene, and prevent pelvic infection.
2. Keep a calm mood and avoid excessive stress.