Which symptom is commonly associated with a molar pregnancy?

In the context of a molar pregnancy, light brown bleeding that persists for weeks is indeed a common symptom. Molar pregnancies, which are a type of gestational trophoblastic disease, can lead to abnormal growth of trophoblastic tissue, and this abnormal tissue can cause a variety of bleeding or discharge. The light brown color often indicates older blood, which can result from the implantation issue or from the expelled tissue in a molar pregnancy. This type of bleeding can be distinct from the heavy bleeding that might be seen in other complications of pregnancy.

On the other hand, heavy red bleeding throughout the first trimester can occur in multiple conditions, including miscarriage but is not characteristic specifically of molar pregnancies. Severe abdominal pain with fever could suggest an infection or other acute issue that is not typical for a molar pregnancy itself. Lastly, irregular fetal movements are not a symptom associated with molar pregnancies, as these pregnancies often do not result in a viable fetus, so fetal movements would not be experienced. Thus, the persistent light brown bleeding is the most aligned symptom with a molar pregnancy diagnosis.