Spotting or bleeding is the most prominent sign of a miscarriage, according to Krissi Danielsson for About.com. Severe abdominal pain is another symptom. A loss of early pregnancy symptoms like breast tenderness and morning sickness is a sign of pregnancy complications. A lack of movement from the baby is another indication of a serious problem.
WebMD notes that a dull pain in the lower back is another sign of a miscarriage, and pelvic cramps are another problem. Fetal tissue passing from the vagina is another indication of fetal complications. Pain in the lower back, pelvis or stomach may last anywhere from a few hours to several days. Blood-clot matter from the vagina is another symptom. A clear or pinkish fluid from the vagina requires medical assistance.
WebMD notes that pain accompanied with bleeding is a more troubling sign. MomsWhoThink.com mentions that lower backaches accompanied with bleeding are another sign of a miscarriage. WebMD points out that bleeding from a miscarriage can occur with or without cramps.
Danielsson claims that severe pain in the abdomen in the early part of the pregnancy is cause for concern, especially if there is pain on a particular side of the abdomen. Preterm labor in the second or third trimester requires the immediate attention of a doctor or a visit to the emergency room. Signs of preterm labor are frequent contractions, dull backaches, menstrual-like cramps and changes in vaginal discharge.