It’s important to achieve accurate diagnosis by identifying the presence of specific amniotic fluid markers in vaginal environment. These tests include measurement of vaginal pH, prolactin, alpha fetoprotein, di-amine oxidase, insulin-like growth factor binding protein-1(IGFBP-1), human chorionic gonadotropin and fetal fibronectin. All these tests have advantages and drawbacks. Up till now there is no gold standard test for PROM.