The influence of the ovarian cycle on the first-step laboratory screening for primary aldosteronism

Objectives: to investigate the influence of the ovarian cycle on aldosterone in low renin hypertensive women. Primary aldosteronism is in fact increasingly recognized as a cause of arterial hypertension and aldosterone has been reported to vary in normal women during the ovarian cycle, usually increasing in the luteal phase. Methods: hormonal levels (LH, FSH, 17 beta-estradiol, progesterone, aldosterone, PRA) were measured at weekly intervals during one menstrual cycle in 26 uncomplicated mild hypertensive women with known low renin levels, after discontinuation of antihypertensive treatment. Statistical analysis was performed by Friedman test, Bonferroni adjusted Wilcoxon test, Fisher exact-test or Chi-square test with continuity correction, as appropriate. Results: Aldosterone and PRA increased from the 7th day (follicular phase) to the 21st day (luteal phase) from 11.2 to 17.8 ng/dL and from 0.23 to 0.35 ng/mL/hr, respectively, (p=0.004), with no significant changes in aldosterone/PRA ratio (ARR) but with an increase in the number of patients with aldosterone levels >15ng/dL (8/26 vs 19/25, p=0.018) or with an ARR >30 if combined with either a minimum PRA value of 0.5 ng/ml/hr or an aldosterone level of >15 ng/dL (7/26 vs 16/25 and 7/26 vs 17/25 respectively, p<0.05). Aldosterone was positively correlated with PRA and progesterone levels. Conclusion: Hyperaldosteronism frequently occurs during the luteal phase of the ovarian cycle in low renin hypertensive women (possibly linked to a progesterone effect); the ovarian cycle may thus be a factor of variability in the performance of parameters and cut-off points commonly used in the first-step laboratory screening for primary aldosteronism.