We were interested to read of the findings of the Finnish group that an increased heart rate measured by 24-h Holter electrocardiogram was not a feature of four women who later developed pregnancy hypertension or pre-eclampsia (Ekholm et al. 1994). Their results are in contrast to those we reported previously of an increased heart rate at 28 weeks of gestation prior to the onset of pre-eclampsia. This was observed in two much larger groups of women. In one, the heart rate was measured by an ambulatory blood pressure recorder, and 17/128 developed pre-eclampsia, whereas in the other, the measurement was made by manual pulse and 57/437 developed pre-eclampsia.

The difference in results between the original and present study may possibly be explained by differences in methods of measurement However, the increased heart rate we observed was an unexpected finding in a much larger series than reported here, and so we will be interested to see if others confirm or refute the original observation.