Which test can confirm the rupture of membranes and the presence of amniotic fluid?

The presence of amniotic fluid and the confirmation of the rupture of membranes can be most accurately identified through the use of Nitrazine paper and the fern test. Nitrazine paper is a pH indicator that changes color in the presence of amniotic fluid, which is alkaline, compared to the more acidic vaginal secretions. When the membrane ruptures, the amniotic fluid leaks and this change in pH can be detected using the paper, providing a straightforward and practical method for confirming rupture.

The fern test provides further confirmation. A sample of the vaginal fluid can be placed on a microscope slide, and when dried and stained, the crystallization pattern formed resembles that of a fern leaf. This pattern is indicative of the presence of amniotic fluid, thus confirming the rupture of membranes.

In contrast, a sonogram is useful for assessing fetal well-being, estimating amniotic fluid volume, and diagnosing certain conditions, but it does not directly confirm membrane rupture. An ECG is irrelevant in this context as it monitors heart activity and not amniotic fluid status. A pelvic exam may assess cervical status or visualize the membranes but does not provide direct confirmation of amniotic fluid presence in the same definitive way as the Nitrazine paper