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Abstract
Background Peak fertility and athletic performance coincide, placing a subset of women into competition with sparse guidance. The Valsalva maneuver has been hypothesized to increase maternal blood pressure and intra-abdominal pressure, resulting in decreased blood flow to the fetus during resistance training.
Objective We present a technique employing three dimensional (3D) power Doppler ultrasound analysis to evaluate placental blood flow during resistance exercise. This technique may be used to prevent fetal injury by guiding training parameters.
Design This is a proof of principal study describing the technique and documenting its use to determine placental blood flow.
Setting This research was conducted in an academic clinical enter. Participants varied from an actively exercising, former collegiate athlete, to participants who performed no scheduled physical activity.
Patients (or Participants) Four normal weight women less than 35 years of age with uncomplicated pregnancies were included.
Interventions (or Assessment of Risk Factors) One repetition maximum (1RM) via modified chest press was determined. Ultrasonography with power Doppler and 3D volume measurements were then performed on the visualized portions of the placenta. The vascular flow index (VFI) was then calculated for each phase.
Main Outcome Measurements VFI was measured during lifting and at rest. The paired t-test was used for statistical analysis. Z scores from previously established normative data (Noguchi, et al 2009) provided benchmarks.
Results VFI was not significantly different between lift and rest phase for any of our participants. All measurements were within a standard deviation of previously established normative data. There were no incidences of fetal bradycardia.
Conclusions 3D power flow Doppler imaging can guide resistance training during pregnancy to prevent fetal injury due to hypoperfusion. Resistance training up to an RM1 of 50lbs did not result in a significant reduction in placental blood flow from resting state in the study population.