Prelabour rupture of membranes: Overview of diagnostic methods

Purpose of review: To evaluate diagnostic accuracy studies for rupture of the fetal membranes (ROM). Recent findings: Sample sizes of recent studies are small and studies used different 'silver standard' definitions for ROM. Therefore, reported results should be interpreted with caution. Over the review period the focus of diagnostic studies has been on two bedside test strips: insulin-like growth factor-binding protein-1 (IGFBP-1) and placental α microglobulin-1 (PAMG-1). Bedside tests improve the confidence of the clinician about their diagnosis. Compared to nitrazine or ferning test alone, IGFBP-1 and PAMG-1 are more accurate. However, compared to the conventional testing (combination of history, ferning, nitrazine, speculum and ultrasound) no statistical difference in accuracy was found. In-vitro PAMG-1 is shown to be superior to IGFPB-1. Furthermore, soluble intercellular adhesion molecule-1 and Axl receptor tyrosine kinase (Axl) seem to be promising new specific biomarkers for diagnosing ROM. Summary: IGFBP-1 and PAMG-1 are the most commonly used bedside tests for diagnosing ROM. Both tests seem to be sensitive and specific, however, evidence is lacking especially in equivocal cases and comparative studies against the real gold standard (amnio-dye) have still not been published. Further effectiveness research is needed before tests can be applied in practice.