CAN 24-HOUR AMBULATORY BLOOD-PRESSURE MEASUREMENT PREDICT THE DEVELOPMENT OF HYPERTENSION IN PRIMIGRAVIDAE

Objective To assess the role of 24-hour ambulatory blood pressure meas urement in the mid-second trimester as a predictive test for the devel opment of hypertension in pregnancy. Design Prospective intervention. Setting The Rotunda Hospital, Dublin. Participants One thousand one hu ndred and two healthy primigravid women. Intervention 24-hour ambulato ry blood pressure measurement at 18 to 24 weeks of gestation. Main out come measures The development of pre-eclampsia or gestational hyperten sion. Results A total of 1048 women had sufficient readings to be incl uded in the final analysis. Of these, 23 (2.2%) developed pre-eclampsi a, 64 (6.1%) developed gestational hypertension and 961 (91.7%) remain ed normotensive. Significantly higher ambulatory blood pressures were recorded in both the pre-eclamptic and gestational hypertensive group compared with the normotensive group. In addition, the gestational hyp ertensive group had significantly higher clinically measured blood pre ssure compared with the normotensive group. There were no differences between the preeclamptic and the gestational hypertensive group for an y of the blood pressure parameters analysed. The best overall predicto r for pre-eclampsia was 24-hour mean diastolic pressure which using a cutoff level of 71 mmHg gave a test with a sensitivity of only 22% and a positive predictive value of 15%. Conclusion Because the absolute d ifferences are small and the overlap between the hypertensive and norm otensive groups large, ambulatory blood pressure measurement, in a hea lthy primigravid population, between 18 and 24 weeks of gestation is n ot a useful predictor of hypertension.