How is menstruation blackened amount less to return a responsibility

Menstruation blackening amount less, if only this time menstruation is such, first of all or consider may be related to pregnancy, first of all is to consider may be threatened abortion or ectopic pregnancy, as long as there is a sexual life of the crowd is must go to blood test HCG. If the recent menstruation is such a situation, but also to see whether abortion damage the endometrium, if from abortion is such a situation, it is necessary to do B ultrasound in ovulation to see the thickness of the endometrium, to see whether there is endometrial loss, intrauterine adhesions.