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Foramen ovale changes in growth‐restricted fetuses
Author(s) -
Kiserud T.,
Chedid G.,
Rasmussen S.
Publication year - 2004
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1002/uog.1079
Subject(s) - medicine , foramen ovale (heart) , fetus , ductus venosus , umbilical artery , cardiology , gestation , intrauterine growth restriction , population , pregnancy , anatomy , patent foramen ovale , environmental health , migraine , biology , genetics
Objective In animal experiments hypoxemia induces an increased shunting through the fetal foramen ovale (FO). Based on the hypothesis that the FO is expanded to permit more flow, the aim of this study was to determine the size of the FO in growth‐restricted human fetuses. Methods Thirty‐one women with singleton pregnancies complicated with growth‐restriction (< 5th percentile) were examined at 24–39 weeks of gestation. The diameter between the FO valve and the atrial septum was determined during maximum excursion in a horizontal transverse section of the fetal heart, and the transverse diameter of the right atrium (RA) was noted. The pulsatility index (PI) was determined in the umbilical artery (UA) and absent or reversed end‐diastolic flow velocity was noted. The measurements were compared with a reference population using Z‐scores. Results In comparison with normally grown fetuses, the growth‐restricted fetuses had a normal RA size ( P = 0.08) but a smaller FO ( P = 0.002), particularly when expressed as a relative size by the ratio FO/RA ( P < 0.0001). This effect on the FO and FO/RA was seen mainly at < 32 weeks of gestation ( P = 0.003 and P < 0.0001, respectively), and was not significant later in pregnancy. There was a tendency towards a negative relationship between relative size of the FO (FO/RA) and progressive placental compromise (overall P < 0.0001). Conclusions Growth‐restricted fetuses maintain a normally grown heart (expressed by the RA diameter) but a reduced FO diameter. The effect is seen before 32 weeks and tends to be more marked in fetuses with pronounced hemodynamic compromise of the placenta. This supports the theory that FO shunting is impaired in severely premature fetuses with placental compromise. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.