Intra-vaginal hydrosonography and cervical length assessment in pregnant women before induction of labour: a modified...

The objective of this study was to demonstrate a new simple technique in introducing saline into the vagina during trans-vaginal scan. This technique will help to identify the cervical length properly when it is difficult to delineate the cervix. This is a prospective study, which included 104 pregnant women who booked to have induction of labour at term over a period of 3 years. Women who were included in the study underwent a transvaginal scan to measure cervical length. Sterile saline was introduced into the vagina using either an ordinary syringe or an Endosampler and the cervical length re-measured. When the outer border of the cervix was not clearly visualised, there was a highly statistically significant difference (p < 0.001) between the medians of pre-and post-saline cervical length measurements. In contrast, no significant difference between the medians (p > 0.05) was detected when the outer border of the cervix was clearly delineated. In those women, who had previous surgery to the cervix, it was very difficult to identify the cervix at all without the saline injection during transvaginal scanning. We conclude that intra-vaginal saline can be used as a contrast medium to help delineate the cervix if it is difficult to identify during transvaginal scan. The Endosampler makes the introduction of the saline into the vagina easy, controlled and well tolerated.