Is Amnisure® useful in the management of women with prelabour rupture of the membranes?

Aims: Prelabour rupture of membranes (PROM), whether at term or preterm, can be a difficult diagnosis to confirm. Clinician uncertainty often leads to unnecessary intervention for risk management reasons. Amnisure (R) is a bedside immunoassay for placental alpha macroglobulin-1 (PAMG-1), which has been shown to have high sensitivity and specificity in the diagnosis of PROM. However, whether the use of Amnisure (R) alters clinical management remains untested. The objective of this study was to assess the clinical utility of Amnisure (R). Methods: A prospective cohort study of 184 women presenting with a history of PROM to a tertiary maternity hospital. Before and after Amnisure (R), the attending clinician assessed and recorded membrane status (PROM or intact), his/her level of confidence in this diagnosis, and the intended management plan. Results: There was clinician uncertainty regarding the diagnosis of PROM in 83 (47%) women. Amnisure (R) significantly increased clinician confidence and led to a change of intended management in 23 (13%) women. In 33 women presenting with possible preterm PROM, seven thought to have PROM before Amnisure (R) had a negative test, leading to a change of management in these women. Conclusions: Amnisure (R) is clinically useful when the clinician is uncertain about the diagnosis but not useful when the clinician is confident about the diagnosis. The use of Amnisure (R) in women where the diagnosis is uncertain is likely to significantly change management, including reduced hospitalisation for women with preterm PROM.