Behaviour of the Foramen Ovale Flow in Fetuses with Intrauterine Growth Restriction.

Background: Foramen ovale (FO) flow may be altered in IUGR. This study was designed to test this hypothesis.

Methods: Forty pregnant women (24-38 weeks) were divided into 3 groups: group I (IUGR), group II (adequate growth and maternal hypertension), and group III (normal controls). Impedance across the FO was assessed by the FO pulsatility index (FOPI): (systolic velocity - presystolic velocity)/mean velocity. Statistical analysis utilized ANOVA, Tukey test, and ROC curves.

Results: Mean FOPI in IUGR fetuses ( n  = 15) was 3.70 ± 0.99 (3.15-4.26); in the group II ( n  = 12), it was 2.84 ± 0.69 (2.40-3.28), and in the group III ( n  = 13), it was 2.77 ± 0.44 (2.50-3.04) ( p =0.004). FOPI and UtA RI were correlated ( r  = 0.375, p =0.017), as well as FOPI and UA RI ( r  = 0.356, p =0.024) and, inversely, FOPI and MCA RI ( r  = -0.359, p =0.023).

Conclusions: The FO flow pulsatility index is increased in fetuses with IUGR, probably as a result of impaired left ventricular diastolic function.