[Circadian rhythm of blood pressure in patients with chronic hypertension and pregnancy].

Background: Ambulatory blood pressure monitoring during 24 hours shows a blood pressure variability. The prevalence of chronic hypertension in pregnant women is 1-5%, so it is important to know the changes in blood pressure and cardiovascular risk and prevent complications to the mother and fetus.

Objective: To know the circadian rhythm of the blood pressure in the chronic hypertensive pregnant patients, through the ambulatory blood pressure monitoring.

Material And Methods: A cross-sectional and descriptive study included chronic hypertensive pregnant patients, with > 20 weeks of gestation. Assessment of factors related to gynaecologic characteristics, according to the inclusion criteria underwent a washout period of two weeks and they were monitored with a Spacelabs 90207 monitor blood pressure. Quantitative variables by Student t test, one-way ANOVA and Pearson correlation were analysed.

Results: 16 chronic hypertensive pregnant patients were included, whose ambulatory blood pressure monitoring for the systolic blood pressure in 24 hours averaged 117.12 ± 5.85 mmHg; 24 hours diastolic blood pressure 71.31 ± 5.89 mmHg; daytime systolic blood pressure 120.18 ± 5.75 mmHg, nocturnal systolic blood pressure 110.31 ± 8.41 mmHg; daytime diastolic blood pressure 75.43 ± 7.32 mmHg, nocturnal diastolic blood pressure 64.25 ± 8.27 mmHg. Significant differences between daytime and night time were found.

Conclusion: 56% of chronic hypertensive pregnant patients had no nocturnal reduction in systolic blood pressure and 43.75% had no nocturnal changes on diastolic blood pressure. The fact that 50% of patients were non-dippers force us to use long-action antihypertensive therapy and obtain control of the blood pressure for 24 hours.