What does it mean if my period hasn't come and the pregnancy test shows one line?

The absence of menstruation with a single line on a pregnancy test may be caused by physiological factors or pathological conditions such as thin endometrium or polycystic ovary syndrome (PCOS). The specific analysis is as follows:

I. Physiological Causes

The absence of menstruation with a single line indicating a negative result on a pregnancy test can occur due to temporary hormonal imbalances caused by fatigue, stress, or medication use. A delay in menstruation of 3–7 days under these circumstances is considered normal, and observation for now is recommended.

II. Pathological Causes

1. Thin Endometrium

If menstruation is delayed for more than one week and pregnancy has been ruled out through examination, this is considered menstrual irregularity. Procedures such as abortion or dilation and curettage may severely damage the basal layer of the endometrium, causing it to become significantly thinner. This affects normal shedding of the endometrium and leads to absent menstruation. Under medical guidance, medications such as progesterone capsules, estradiol valerate tablets, or estradiol tablets may be prescribed for regulation.

2. Polycystic Ovary Syndrome (PCOS)

Elevated levels of androgens and abnormal luteinizing hormone (LH) and follicle-stimulating hormone (FSH) disrupt ovulation, resulting in the absence of both pregnancy and menstruation. Under medical supervision, treatment may include medications such as progesterone capsules, cyproterone acetate combination tablets, or ethinylestradiol-cyproterone acetate tablets to regulate the cycle.

Additionally, conditions such as cervical adhesion or premature ovarian failure could also be responsible. It is recommended to promptly visit a hospital for ultrasound and sex hormone panel testing, and receive targeted treatment based on the underlying cause.