In the late stages of pregnancy, if abnormal vaginal discharge occurs, it is necessary to consider whether there has been premature rupture of membranes. The symptoms of premature rupture of membranes include abnormal vaginal discharge, which sometimes can be heavy and, at other times, may be less. It is often accompanied by a feeling of warmth, without any pain symptoms. If it is unclear whether the condition is due to premature rupture of membranes or urinary leakage, it is recommended to visit a hospital for examination. Doctors can distinguish between premature rupture of membranes and urinary leakage using pH paper, and sometimes further ultrasound examinations are needed to monitor the amniotic fluid volume, which can determine if there has been a premature rupture of membranes.