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® 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® alters clinical management remains untested. The objective of this study was to assess the clinical utility of Amnisure®.

Methods: A prospective cohort study of 184 women presenting with a history of PROM to a tertiary maternity hospital. Before and after Amnisure® , 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® 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® had a negative test, leading to a change of management in these women.

Conclusions: Amnisure® 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® in women where the diagnosis is uncertain is likely to significantly change management, including reduced hospitalisation for women with preterm PROM.