OBJECTIVE: The preload index (PLI) has been shown to increase in the recipient fetus of twin-twin transfusion syndrome in the presence of uterine contractions. The objective of this study was to determine whether there are changes in PLI in the presence of uterine contractions in normal fetuses. METHODS: Inferior vena cava blood flow was measured using Doppler sonography in 45 normal fetuses at 18-41 weeks' gestation in the presence of uterine contractions and during quiescence and the PLI was compared between groups. RESULTS: There was a highly significant difference (P < 0.0001) between the mean +/- SD PLI in fetuses in the absence (0.235 +/- 0.07) and in the presence (0.534 +/- 0.183) of uterine contractions. CONCLUSION: Uterine contractions appear to increase fetal preload conditions in normal pregnancy. Copyright 2003 ISUOG. Published by John Wiley & Sons, Ltd.
OBJECTIVE: The preload index (PLI) has been shown to increase in the recipient fetus of twin-twin transfusion syndrome in the presence of uterine contractions. The objective of this study was to determine whether there are changes in PLI in the presence of uterine contractions in normal fetuses. METHODS: Inferior vena cava blood flow was measured using Doppler sonography in 45 normal fetuses at 18-41 weeks' gestation in the presence of uterine contractions and during quiescence and the PLI was compared between groups. RESULTS: There was a highly significant difference (P < 0.0001) between the mean +/- SD PLI in fetuses in the absence (0.235 +/- 0.07) and in the presence (0.534 +/- 0.183) of uterine contractions. CONCLUSION: Uterine contractions appear to increase fetal preload conditions in normal pregnancy. Copyright 2003 ISUOG. Published by John Wiley & Sons, Ltd.