AN ULTRASOUND STUDY OF GESTATIONAL AND POSTURAL CHANGES IN THE DEEP VENOUS SYSTEM OF THE LEG IN PREGNANCY

Objective To investigate gestational and postural changes in diameter and blood flow in the proximal deep leg veins during pregnancy. Design A longitudinal, prospective observational study. Setting The ultrasou nd department of a teaching maternity hospital. Population Twenty-four healthy women with uncomplicated singleton pregnancies.Methods Real-t ime and duplex Doppler ultrasound assessments of the vessel diameter, flow velocity and respiratory flow fluctuation in the proximal deep le g veins of women serially measured from the first trimester of pregnan cy to six weeks postnatally. Main outcome measures The effects of incr easing gestation and the adoption of the left lateral position on the above parameters. Results An increase in vessel diameter and a fall in flow velocity with increasing gestation was observed. However, no cha nge in venous flow variation was observed. Delivery had reverse effect s. Flow velocity was slower in the left than the right legs, but on ad option of the left lateral position an increase in flow velocity and v enous flow variation was observed in both legs during pregnancy. Concl usions These data are consistent with the observed increase in inciden ce and pattern of deep venous thrombosis in pregnancy and may aid inte rpretation of duplex Doppler ultrasound examinations for deep venous t hrombosis in pregnancy. Postural changes should be part of this evalua tion. The gravid uterus may not be the sole cause for postural changes in deep venous flow velocity.