- Both fetal weight and the growing uterus will compress the inferior vena cava, which transports blood from the legs back to the heart.
- Pregnant women have almost one and one-half times the normal blood volume to nourish both mother and baby.
- Hormonal changes in pregnancy cause venous walls to relax and dilate, accommodating the higher blood flow.
All three changes during gestation can place undue stress and tension on venous circulation causing veins in the lower body to stretch and swell. Venous blood flow, unlike arterial blood flow, does not occur in conjunction with the pumping action of the heart. Instead, the veins rely on one-way valves to keep blood from flowing backward due to the effect of gravity.
Fetal and Uterine Factors Contributing to Varicose Veins
Venous blood returning to the heart from the legs is already fighting gravity along its journey. Picture a heavy object pressing on the large veins in the abdomen and thighs, which then creates restrictions on blood flow. Blood would pool below the compressed areas, and the veins in the legs would need to dilate and stretch to accommodate the congestion. This happens as both the fetus and uterus grow during pregnancy. The end results are varicose veins in the thighs and legs. Most times, superficial veins also dilate, resulting in superficial spider veins. These spider veins are common on the ankles, back of the knees, and even on the abdomen.
Increased Blood Volume
According to the American College of Obstetrics and Gynecology. Blood volumes in pregnancy increase to over 50% more than non-pregnant women. This amounts to over one liter of extra fluid circulating within the veins. The largest part of the increase occurs in the last eight weeks of pregnancy, when both the fetus and uterus are growing in size rapidly. Increased blood volume takes an already compressed venous system below the abdomen. The increased plasma volume along with compression of the inferior vena cava can further dilate veins in the lower body, further contributing to the development of varicose veins.
Hormonal Effects on Venous Walls
Progesterone secreted during pregnancy makes veins more fragile. The weakened veins dilate and stretch more to accommodate both the increase in blood volume and pooling caused by compression of the inferior vena cava. The effects are like the thinning of a balloon when there is too much air blown into it. Superficial spider veins may rupture, creating bruising and superficial hemorrhages under the skin. This occurrence is also a contributing factor in the development of varicose veins during pregnancy.
How to Prevent or Treat Varicose Veins During Pregnancy
The good news is that in most cases, varicose veins disappear within three to four months after delivery of your newborn baby. Sometimes, such as multiple pregnancies and genetic predisposition, they may become permanent. Regardless, there are many treatments available to eliminate or diminish their appearance after pregnancy. There are also several methods you can use to prevent and lessen their appearance during pregnancy:
- Regular low impact cardiac exercise during pregnancy will increase circulation and prevent blood from pooling in the lower legs.
- Frequent rest periods, including elevating the legs above the level of your heart can also increase blood flow.
- The use of compression stockings during daily activities can also deter blood from pooling in the extremities. Be sure to fit compression stockings when your legs are the least swollen to ensure the proper fit. Also, compression stockings should not be tight around the upper legs but should gradually tighten around the ankles.
- Avoid prolonged sitting or standing and crossing your legs above at the knees to maintain open channels for venous return from the lower legs.
When to Notify your Doctor or Vein Specialist
Varicose veins during pregnancy are seldom harmful and usually resolve on their own after delivery. You should, however, notify your doctor or vein specialist if they do not resolve within several months after delivery. Seek immediate treatment if the skin around the area becomes discolored or hot to the touch. Also, notify your doctor if inflammation, redness, and fever occur. Contact us online or call The Vein Centre today 615-269-9007 for all your vein needs!