DVT can lead to a dangerous condition called pulmonary embolism. This is when a blood clot travels to the lungs. Research shows that any type of travel lasting 4 hours or more—whether by car, train, bus, or plane—doubles the risk of DVT. Being pregnant is an extra risk factor for DVT.
During the third trimester (25 to 40 weeks), many healthcare providers and midwives advise staying within a 300-mile radius of home because of potential problems such as high blood pressure, phlebitis, and false or preterm labor.