Abstract Prelabor rupture of membranes (PROM) is a common obstetrical problem, but its diagnosis is frequently problematic. Lacking a gold standard, the diagnosis is equivocal in some 10% of cases. We performed a systematic review to assess the accuracy of several tests for the diagnosis of PROM in these equivocal cases. We performed an electronic search in PubMed, Embase, DARE and the Cochrane Library and reference lists for potentially missed articles. No language restrictions were used. Only accuracy studies for diagnostic methods for PROM in women with equivocal PROM were selected. The studies were scored according to STARD and QUADAS guidelines. Based on the full description of reference and index tests, an expert panel finally decided whether the selected articles were of sufficient quality to be included. We identified 3864 studies of which 146 full manuscripts were obtained. We excluded 133 due to multiple reasons. The remaining 13 studies were scored by an expert panel. Only three articles with a total of 155 patients fulfilled all criteria. These articles tested three different methods, pH measurement (64 patients), insulin-like growth factor binding protein-1 (ILGBP-1, 83 patients) and alpha fetoprotein (AFP, 8 patients). Sensitivity varied from 88% (pH) to 100% (AFP), specificity varied from 56% (ILGPP-1) to 100% (AFP). Based on the limited evidence on the accuracy of tests to diagnose ruptured membranes, we conclude that the use of a particular test cannot be recommended.