The first menstrual period after miscarriage is dark and small in volume. This is due to the discharge of some residual tissues from the endometrium after miscarriage, which is considered normal. However, if it is accompanied by fever or severe abdominal pain, foul-smelling menstruation and other symptoms, the presence of incomplete miscarriage or co-infection needs to be considered and further investigations such as gynaecological examination and ultrasound can be done.