Dynamics of the Septum Primum in Fetuses with Intrauterine Growth Restriction

Purpose. To test the hypothesis that the linear displacement of the septum primum (SP) is lower in fetuses with intrauterine growth restriction (IUGR) than in fetuses with appropriate growth for gestational age (AGA). Methods. In a cross-sectional study, the ratio between the SP displacement and left atrial diameter (excursion index [EI]) was compared in 27 fetuses with IUGR (group 1), 24 fetuses with AGA of hypertensive mothers (group 2), and 35 controls (group 3). Flow through the atrioventricular (AV) valves and the umbilical artery resistance index (RI) were also compared. Results. Irrespective of gestational age, mean El in group 1 (0.41 +/- 0.07) was significantly lower than in group 2 (0.48 +/- 0.07; p < 0.001) and than in group 3 (0.50 +/- 0.06; p < 0.001), with no significant differences between groups 2 and 3. In fetuses over 30 weeks of gestation of group 1, El was lower (0.38 +/- 0.05) than in group 2 (0.49 +/- 0.07) and group 3 (0.51 +/- 0.06; p < 0.001). There was significant inverse correlation between El and RI (r = 0.46; p < 0.01) and no correlation between El and AV flow velocities. Conclusions. SP mobility is reduced in fetuses over 30 weeks with IUGR compared with AGA fetuses. These findings may depend on alterations of left ventricular diastolic function and are correlated to the degree of placental insufficiency. (C) 2009 Wiley Periodicals, Inc. J Clin Ultrasound 37:342-346, 2009; Published online in Wiley InterScience (www. interscience. wiley.com). DOI: 10.1002/jcu.20582