This guideline advises that the ‘Vision Amniotic Leak Detector’ can be used. This sounds like a rather handy device. The idea is to allow us to reliably exclude amniotic fluid leak as a cause of ‘wetness’ in pregnancy, thus reducing the need for onward referral and also reducing the need for internal examinations.
It is a pantyliner that the lady places in her underwear. It can be read as soon as it is sufficiently wet. There is a strip in the centre of the liner, which is removed and placed on a ‘drying unit’ for 30 mins. It turns blue-green if the pH is above 5.2. Normal vaginal pH is 3.5 to 4.5. Amniotic fluid is normally 6.5 or above. Vaginal infections can also give a high pH.
If the strip stays yellow, an amniotic leak can therefore be ruled out. If it turns colour, they need an internal examination or referral to evaluate for amniotic leak or infection.