A postpartum woman on the 12th day after the normal delivery complains of pain localized in her left gastrocnemius muscle. Body temperature is 37,2°C; pulse is 85/min, rhythmic; blood pressure is 128/80 mm Hg. Mammary glands are soft and painless. The uterus is behind the pubis. The left leg in the area of gastrocnemius muscle is by 3 cm larger than the right leg in the diameter. Internal organs present no pathologies. What complication can be suspected?