Increased discharge at 39 weeks of pregnancy may be a sign of approaching labor, but it may also be an abnormal condition such as vaginitis or premature rupture of membranes, which needs to be diagnosed differently after completing relevant examinations. 1. Premature labor: if there is increased vaginal discharge before labor, and there may also be brown discharge, it may be a symptom caused by the shedding of cervical mucus plug, which indicates that labor may start in recent days, but the specific time varies from person to person. 2. If the discharge increases, and at the same time you find that you have symptoms such as hardness, tightness, distension, lumbago and swelling, which cannot be relieved and have a certain regularity, accompanied by vaginal bleeding, fetal head descent and dilatation of the uterus, it means that you have entered the stage of labor, at this time you need to understand the contractions through fetal heart monitoring, and go to the hospital in time to be ready for labor; 3, premature rupture of fetal membranes: if If there is a sudden increase in discharge, the amount of discharge is relatively small but continuous, the liquid is thin like water, and may be mixed with feces or fetal fat, when the pregnant woman changes position, there may also be liquid from the vaginal opening, you need to go to the hospital for vaginal fluid smear to check whether it is premature rupture of fetal membranes and related treatment; 4, vaginitis: if you find that the discharge increases and is accompanied by vulvar itching, burning and other uncomfortable symptoms, it may be caused by Vaginitis may be caused by vaginal discharge, which can usually be diagnosed by vaginal discharge examination and treated under the guidance of a doctor.