[Which biological test to confirm rupture of membranes?]

Rupture of membranes (ROM) occurs frequently and requires specific management depending on gestational age in order to avoid maternal and fetal complications. In 80% of cases, ROM is associated with large amniotic fluid (AF) leakage making diagnosis easy. The aim of the current review is to precise which biological test is useful for the physician facing ambiguous clinical picture. Vaginal pH assessment demonstrates alkalinisation (6.5-7.5) when AF is present (sensitivity 73-91%, specificity 72-83%). Drying test, fern test or fetal cells staining have been supplanted by detection of AF proteins. Diamine oxidase activity required specific radioanalytical assay leading to restrictive use and progressive abandon. Immunoassay tests detecting Insulin-like Growth Factor-Binding Protein-1 (IGFBP-1) or Placental Alpha 1-Microglobulin (PAMG-1) are currently considered as the most useful tools for ROM diagnosis. Literature fails to provide sufficient evidence that one of these two approaches should be favoured. Distinction between IGFBP-1 and PAMG-1 remains controversial as they seem to correspond to the same molecule.