Diagnosis of foetal membrane ruptures: Placental alpha‑microglobulin‑1 to the rescue
Context: Pre‑labour rupture of membranes (PROM) is a common obstetric complication which presents a diagnostic challenge, especially in equivocal cases. Standard methods of diagnosis are limited by high false positives and negatives. This study compared the accuracy of a biomarker placental alpha microglobulin‑1 (PAMG‑1) with the traditional methods of diagnosis.
Objective: To compare the accuracy of PAMG‑1 in cervicovaginal secretions with other standard methods in the diagnosis of PROM.
Materials and Methods: A longitudinal prospective study was conducted among women with symptoms and signs of PROM at the Lagos State University Teaching Hospital. Standard tests and PAMG‑1 assay were compared with the reported final diagnosis at delivery. Descriptive analysis was done using the Statistical Package for Social Sciences (SPSS) version 19.
Results: A total of 140 consenting pregnant women were recruited in the study. An initial diagnosis of PROM was made in 67 patients (47.9%) using the standard methods of diagnosis whereas PAMG‑1 immunoassay using Amnisure ROM test diagnosed PROM in 86 patients (61.4%). Upon review of patients’ clinical records, 88 women (62.8%) had a final diagnosis of PROM. In the final analysis, PAMG‑1 assay had a sensitivity of 97.7%, specificity 100%, PPV 100% and NPV 96.7%. The standard methods had a sensitivity 76.1%, specificity 92.2%, PPV 90.1% and NPV 70.4%. PAMG‑1 had a highest accuracy of 98.6%, followed by nitrazine test 89.3%, pooling of liquor 83.5% and fern test 51.4%.
Conclusion: The immunoassay of PAMG‑1 had a higher diagnostic accuracy and is recommended for the diagnosis of PROM.
Key words: Prelabor rupture of fetal membranes; placental alpha microglobulin-1; traditional diagnostic tests.