Effect of fetal magnetic resonance imaging on fetal heart rate patterns

Objective: Our aim was to record the fetal heart rate before and during magnetic resonance imaging to observe the effects of the magnetic resonance imaging process on fetal heart rate parameters during imaging. Study Design: Fetal heart rate recordings were obtained in 10 pregnant volunteers at the time of magnetic resonance imaging. All the pregnant women were at term (37–41 weeks) with singleton fetuses in the cephalic presentation. The scanning was performed on a 0.5-T purpose-built superconductive magnet by use of echo-planar imaging. The fetal heart recordings were obtained with a modified Sonicaid Meridian 800 (Oxford) Doppler ultrasound monitor. Recordings of the fetal heart were made for a period of at least 15 minutes outside the magnet and then for at least 15 minutes inside the magnet. Results: There were no significant changes in any fetal heart rate parameters before and during the magnetic resonance imaging, as determined by the Wilcoxon matched-pairs signed-ranks test (P> .3). Conclusions: This is the first report of fetal heart rate recording during magnetic resonance imaging of the fetus. Magnetic resonance imaging does not produce demonstrable effects on fetal heart rate patterns.