Final answer:
During pregnancy, increased blood volume predisposes to varicose veins.
Step-by-step explanation:
During pregnancy, factor that predisposes to varicose veins is increased blood volume. Varicose veins are veins that become enlarged and twisted due to ineffective valves. The increased blood volume during pregnancy helps manage the demands of fetal nourishment and waste removal. As the fetus grows, the uterus compresses pelvic blood vessels, hampering venous return, causing varicose veins to develop.