38 weeks with brown discharge but no pain consider the first sign of labor, may also be other causes, such as placenta praevia, cervicitis and so on. 1. Aura of imminent labor: 38 weeks the fetus has matured, at any time may be born, the fetal membrane near the mouth of the cervix and the uterine wall separation, capillary rupture, a small amount of vaginal blood secretion, which is a normal physiological manifestation of the birth of the launch of the birth of a normal physiological manifestation. This is a normal physiological manifestation before labor starts. Most pregnant women will be accompanied by tightness in the stomach, swelling and pain in the lower abdomen, lower back pain and irregular contractions. 2. Placenta praevia: the lower edge of the placenta is adjacent to or covers the cervical opening, i.e., placenta praevia, which will cause small amount of painless vaginal bleeding without any cause in late pregnancy or at the time of labor. 3. Cervicitis: acute and chronic inflammation of the cervix will lead to congestion and edema of the cervical mucosa, and in late pregnancy, the cervical opening will gradually shorten, and then there will be a small amount of vaginal bleeding, sometimes brown. The brown discharge at 38 weeks of pregnancy but no pain may also have other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.