What does it mean if I Missed period but negative pregnancy test?

Missed period but negative pregnancy test can have several possible explanations:

1. Early Pregnancy: It's possible that you're pregnant but the levels of human chorionic gonadotropin (hCG), the hormone detected by pregnancy tests, are still too low to be detected. Repeat the pregnancy test in a few days or a week to see if the result changes.

2. Implantation Bleeding: Some women experience light bleeding or spotting around the time their period is due, which could be a sign of implantation of the fertilized egg in the uterus. Implantation bleeding is usually lighter than a menstrual period and may last for a few days.

3. Irregular Menstrual Cycles: Occasional variations in the timing of menstrual periods are common, and many women experience irregular cycles, especially during the years before menopause or in adolescence.

4. Stress and Lifestyle Changes: Stress, dietary changes, extreme exercise, or significant disruptions in routine can sometimes affect the timing of menstrual cycles.

5. Medications or Medical Conditions: Certain medications, such as hormonal contraceptives, thyroid medications, or some antidepressants, can affect menstrual cycles. Medical conditions like thyroid issues, polycystic ovary syndrome (PCOS), or hormonal imbalances can also disrupt regular menstrual cycles.

If you're experiencing a missed period and a negative pregnancy test, it's generally advisable to consult with a healthcare provider to determine the cause and discuss appropriate next steps. They may recommend additional tests or evaluations to identify any underlying medical conditions or provide further guidance.