Which of the following is NOT a method to diagnose PROM?

The diagnosis of premature rupture of membranes (PROM) primarily relies on clinical evaluation and direct methods that assess the presence and nature of amniotic fluid. Methods such as taking a detailed history and performing a thorough physical examination are essential. This includes noting the patient's symptoms, the timing of rupture, and any associated signs. Basic pH testing of vaginal fluid and observing the pooling of vaginal secretions are also commonly used diagnostic tools that help indicate the presence of amniotic fluid.

Ultrasound-guided amniocentesis, however, is not a standard method for diagnosing PROM. This procedure is more invasive and is typically reserved for other indications, such as genetic testing or assessing fetal lung maturity, rather than for immediate evaluation of PROM. While amniocentesis can confirm the presence of amniotic fluid, it is not routinely performed solely to diagnose PROM due to its invasiveness and associated risks. Therefore, other available and less invasive methods are preferred in clinical practice to assess PROM.