Detection of hysteroscopic fluid in the pouch of Douglas: a prospective cohort study about the predictability of bilateral tubal occlusion.

When CDS fluid does not change after hysteroscopy, this is a sensitive test for tubal occlusion and further testing may be warranted. However, if there is an increase in CDS fluid after hysteroscopy, particularly for a patient without fluid present prior, this is both sensitive and specific for unilateral or bilateral tubal patency.