The first sign that the uterus has ruptured is that the contractions stop completely. Other signs rapidly follow.
Tender swollen abdomen
Tenderness is pain elicited when you touch the abdomen. The abdomen is tender because of the rupture in the uterus and irritation caused by blood accumulating in the abdominal cavity. The abdomen appears distended (swollen) because the uterus is initially totally wrapped around the fetus and blood is escaping into the abdominal cavity. Bowel movement will be reduced or absent (paralytic ileus) so you will not be able to hear bowel sounds with your stethoscope. The bladder may also be obstructed, which contributes to the swelling and tenderness. As time passes, infection may develop in the abdomen, which will cause additional swelling.
Easily palpable fetal parts, absent movement and fetal heart sounds
The fetus cannot survive long in a ruptured uterus. After the initial wrapping of the uterus tightly around its body, parts of the fetus may emerge through the rupture, or the entire fetus may escape from the uterus into the abdominal cavity. When this happens, if you palpate the abdomen, only the abdominal wall will be between your hand and the fetus, so you will be able to feel the fetal parts easily. If the baby has died, the mother will not feel it moving, and you will not be able to hear a fetal heartbeat.