Coital retrograde menstruation as a risk factor for pelvic endometriosis

To investigate coitus during menstruation as a possible predisposing factor for endometriosis 78 patients were asked about their coital habitus during menstruation and subsequently were examined by ultrasound transabdominally, transvaginally, or both, before laparoscopy or surgery. MRI was used in six patients only. There was a statistically significant relationship between endometriosis and coital practice during menstruation. The incidence of endometriosis in patients with history of coitus in menses was 66% while the incidence was 34% in patients with no such history. It is concluded that coitus during menses could be a predisposing factor for endometriosis