Coitus and antepartum haemorrhage.

The relationship of coitus to antepartum haemorrhage was explored in a longitudinal study of 56 568 pregnancies. The frequency of the haemorrhages was 19/1000 births when women reported no recent coitus compared with 30/1000 when there had been recent coitus (p less than 0.001). The frequency of the bleeding increased with the frequency of coitus. The correlation between coitus and bleeding was independent of other factors known to increase the risk of antepartum bleeding including cigarette smoking, hypertension, advancing maternal age and placenta praevia.