Objective: To evaluate the accuracy of colpohydrosonography for measuring uterine depth.
Study design: Uterine depth was assessed in 64 women being evaluated for assisted reproductive technology treatment in a high-volume private practice. After noting the cavity depth by standard transvaginal ultrasonography, a small amount of saline (10-20 mL) was instilled into the vagina, and the uterine depth was remeasured. The results were compared to the depth measured by mechanical sounding performed during a different evaluation. The sonographic measurements of uterine cavity depth were correlated with mechanical sounding.
Results: Colpohydrosonography correlated strongly with uterine depth as measured by mechanical sounding (r = .89), while standard vaginal ultrasound correlated less well with sounding (r = .66). There was < 5% difference between colpohydrosonography and mechanical sounding in 89% of patients, while 48% of standard vaginal ultrasounds varied from sounding by > 10%.
Conclusion: Colpohydrosonography is a simple procedure that more accurately measures uterine cavity depth than conventional transvaginal ultrasound alone. Improved precision of cavity depth measurement could have implications for improving embryo placement during assisted reproductive technology treatment.