The deep venous system in the puerperium: An ultrasound study

Objective To study the vessel wall diameter and blood flow velocity within the proximal deep venous system of the leg in the puerperium and to compare these measures with respect to the left versus right leg, 4th versus 42nd postnatal day, and vaginal versus caesarean delivery. Design A combined longitudinal and cross-sectional observational study. Setting The ultrasound department of a teaching maternity hospital. Results A reduction in vessel diameter and an increase in flow velocity was observed between the 4th and 42nd postnatal day. Vessel diameter was greater and flow velocity was reduced in the left compared to the right leg. In those delivered by caesarean section, a trend towards reduced flow velocity in the proximal deep leg veins was observed when compared with those delivered vaginally. Conclusions These data suggest possible physiological mechanisms behind previous clinical observations relating to the period of greatest risk of deep vein thrombosis in the puerperium, the relative preponderance of left sided deep vein thrombosis and the risk of deep vein thrombosis associated with caesarean section.