Objective Analyse venous haemodynamics in healthy primigravidae during pregnancy and in the postpartum. Methods Cohort with primigravidae evaluated in the three trimesters of pregnancy and postpartum. Duplex evaluated venous diameters and reflux; air plethysmography evaluated venous filling index, ejection fraction, residual volume fraction and outflow fraction in both limbs. Results During pregnancy, diameters increased in bilateral common femoral and right infravalvar great saphenous, but returned to first trimester values after delivery. Reflux developed in one woman (5%) in the second trimester and in two more women (15%) in the third trimester. No reflux was detected in postpartum. Bilateral venous filling index was higher during pregnancy. Bilateral ejection fraction and residual volume fraction did not change. Bilateral outflow fraction increased progressively. The right limb outflow fraction in left lateral decubitus was similar. All changes returned to first trimester values after delivery. Conclusions Healthy primigravidae presented changes in lower limbs' veins during pregnancy: diameters in bilateral common femoral and infravalvar great saphenous veins increased; new reflux was developed in 15% of women, but there was no venous hypertension. Calf muscular pump function did not change. All changes returned to first trimester values after delivery.
Keywords: Pregnancy; air plethysmography; duplex scan; venous haemodynamics; venous reflux.