The endometrium of the uterus does not thin during a caesarean section. Thinning of the endometrium may be caused by infection of the uterine cavity secondary to a caesarean section or by the removal of residual intrauterine pregnancy tissue. Endometrial thinning is associated with gynaecological inflammation and surgical damage to the uterus. Patients should go to the hospital for relevant investigations and then seek appropriate treatment.