4. How is the diagnosis of PPROM best achieved?
The diagnosis of spontaneous rupture of the membranes is best achieved by maternal history followed by a sterile speculum examination.
Ultrasound examination is useful in some cases to help confirm the diagnosis.
The presence of a pool of fluid in the vagina at sterile speculum examimation is highly suggestive of amniorrhexis.A range of tests have been used to confirm membrane rupture;the most widely used has been the Nitrazine test, which detects pH change.10,11 Other tests which have been used include microscopic examination of the vaginal fluid for the characteristic ferning of the crystalline pattern of dried amniotic fluid owing to its sodium chloride and protein content,12,13 examination for lanugo hair12 and fetal epithelial cells stained with Nile blue.14
RCOG Green-topGuidelineNo.44 2of12 ©RoyalCollegeofObstetriciansandGynaecologists