Membranous Dysmenorrhoea is defined as sudden sloughing of thickened endometrium as a whole with the shape of the uterine cavity, which may be associated with severe abdominal cramping. Although not rare, there are few cases described. It's more common in young females who were on either combined or progesterone only contraceptive pill, causing the decidualization of the endometrium. Due to its similarities to a gestational sac, miscarriage is the main differential diagnosis.

The authors report a case of a 43-year-old woman under no hormonal medication presenting her first episode of Membranous Dysmenorrhea with no other symptoms besides the loss of decidual cast.