Hallow Dear, Such a scanty bleeding during menses is suggesting mainly of the hormonal imbalance. Even Thyroid dysfunction (which also is a hormonal imbalance) can lead to such low bleeding during menstruation. Please get your blood tested for FSH, LH, Oestrogen, Progesterone, Prolactin, T3, T4 and TSH. Mostly the cause would be detected in this profile. Additional ultrasonography would also inform you about the condition of your ovaries and endometrium. Tuberculosis of the endometrium also would cause such scanty bleeding; however, it does not cause such acute changes; it would have been over months or years. The other most common cause could be stress. If you are under any stress, please try to get rid of it, may be with some professional help from counsellor. As a first step, you may take Oestrogen dominant birth control pills for five days to observe the withdrawal bleeding after 4-7 days. If the bleeding is normal, you may observe your menses for three months before taking any drastic step; if not, please report t your Gynaecologist with the reports of the investigations I have suggested you. Anaemia would cause heavy bleeding rather than scanty bleeding. So you can set that possibility aside. I hope this helps you. Dr. Nishikant Shrotri