The effect of maternal exercise on umbilical artery blood flow in pregnancy-induced hypertension

Seventeen in-patients with pregnancy-induced hypertension (PIH) in the last trimester of pregnancy underwent an exercise stress test. The mean exercise intensity achieved was 66% (55-77%) of submaximal exercise. The mean maternal heart rate rose significantly from a mean of 89 beats per minute (64-110 bpm) to a mean of 144 bpm (120-168 bpm) after exercise. The mean systolic blood pressure rose significantly from a mean of 149 mmHg (130-170 mmHg) to a mean of 171 mmHg (150-190 mmHg). The diastolic blood pressure rose from a mean of 102 mmHg (100-110 mmHg) to a mean of 106 mmHg (100-115 mmHg). In patients with systolic blood pressure of 180-190 mmHg, their fetuses had significantly higher systolic/diastolic (S/D) ratios before and after exercise than those with blood pressure of 150-170 mmHg. The PI showed sharp fluctuations but the changes were not significant. The mean S/D and the PI decreased at 2, 4, 6 and 8 minutes of recovery from baseline values at rest. Subsequently it rose significantly to peak at 20 minutes of recovery. No evidence of ill effect from the exercise test was noted on any of the mothers or their fetuses. All pregnancies resulted in a good outcome.