Premature rupture of membranes (PROM) refers to the rupture of amniotic fluid before labor. The most common diagnostic method for PROM is based on the clinical symptoms of the patient, mainly intermittent vaginal discharge. PROM can be confirmed using pH test strips specific for this condition. Ultrasound can be used as an auxiliary diagnostic method for PROM because most pregnant women with PROM will show a decreased amount of amniotic fluid during an ultrasound. However, the specificity of using ultrasound to determine PROM is not strong. Although the membranes may rupture, amniotic fluid can still be continuously produced, so some pregnant women may still have a normal amount of amniotic fluid during an ultrasound. Therefore, in most cases of PROM, a reduction in amniotic fluid can be observed through ultrasound, but there are cases where the amniotic fluid level appears normal. In such instances, it's essential to analyze the patient's clinical symptoms.