Pregnancy and Varicose Veins – why do pregnant women get varicose veins?

There are dramatic changes in the female body during pregnancy and often varicose veins and thread veins appear for the first time. I will discuss the main changes that occur in the venous circulation and I will review the evidence for a causal link between varicose veins and pregnancy.

During the last trimester of pregnancy there is an increase in the maternal circulating blood volume to provide increased oxygen and nutrient carrying capacity for the developing fetus. Most of this increased circulation is accommodated in the veins of the legs. This is also facilitated by increases in progesterone and estrogen which cause relaxation and dilatation of the veins. The presence of the developing foetus in the female pelvis tends to obstruct venous return.
Despite these 3 major changes, a number of observations suggest that pregnancy does not cause varicose veins.

    1. The Edinburgh Vein Study shows that the prevalence of varicose veins is not higher in women which might be expected if pregnancy is a major cause of varicose veins. In fact, it suggests the opposite, that the prevalence of varicose veins may actually be higher in men compared to women (Evans et al. J Epidemiol Community Health 1999;53:149-153 – The Edinburgh Study).
    2. Secondly, the age distribution of varicose veins shows a steady rise in the prevalence of varicose veins with increasing age. If pregnancy caused varicose veins, we might expect a female “spike” at the age range 20-40 years, when most women have children. This is not the case (J Prev Med 1988;4:96-101 – The Framingham Study).
    3. Finally and perhaps most conclusively, vascular Surgeon Linda de Cossart and her colleagues in Chester, England showed that women who had no reflux before pregnancy did not develop reflux or varicose veins during pregnancy when examined by duplex ultrasound (Br J Obstet Gynaecol 1999;106:557-62). However in those women who already had reflux and varicose veins before pregnancy, these deteriorated during pregnancy (Eur J Vasc Endovasc Surg 1999;18:294-9). 

Mark Whiteley a vein specialist in Guildford has reviewed the evidence in his book “Understanding Venous Reflux the cause of varicose veins and leg ulcers”.
There is very little evidence of a causal link between pregnancy and varicose veins despite all the other body changes that occur.  

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