Should Aldosterone Suppression Tests Be Conducted During a Particular Phase of the Menstrual Cycle, and, If So, Which Phase?

Results of a Preliminary Study

Ashraf H. Ahmed; Richard D. Gordon; Gregory Ward; Martin Wolley; Cynthia Kogovsek; Michael Stowasser

Disclosures

Clin Endocrinol. 2015;83(3):303-307. 

In This Article

Results

Twenty-two women completed the study (mean age 42 ± 5 years SD). None were receiving hormonal contraception. Twelve women completed FST during the follicular phase (mean age 42 ± 4 years SD), and 10 women completed the test during the luteal phase (mean age 42 ± 5 years SD). In all subjects, FST commenced and finished during the same phase (that is, there were no subjects in whom the FST was conducted during the transition between the two phases). The term transition is used to describe the situation when transition from one phase of the cycle to another might occur during the conduct of the FST. For example, if ovulation occurred during the FST, the test could start during the follicular phase and finish during the luteal phase. The FST was positive in 18 patients and negative in four. Among the 18 positive, 14 completed AVS and 4 did not proceed for AVS. Seven of the 14 who completed AVS were found to have unilateral aldosterone production. Two of the seven with unilateral aldosterone production completed FST during the luteal phase, and five completed FST during the follicular phase. Of the seven who were found to have bilateral aldosterone production, four completed FST during the luteal phase and three completed it during the follicular phase. Of the four patients who did not proceed to AVS, FST was performed during the follicular phase in one and during the luteal phase in the remaining 3. Three of the patients with negative FST completed the FST during the follicular phase. The fourth completed the test during the luteal phase and the day of the ovulation should have been the first day of FST. However, of the 10 who completed FST during the luteal phase, this patient was the only one whose progesterone levels (which ranged from 4 to 10 nmol/l during the test) were low, suggesting a probable anovulatory cycle. This patient was therefore excluded from further analysis, leaving nine women who completed FST in the luteal phase, and in whom the test was positive in every case.

As shown in Table 1 and Fig. 1, median progesterone values in the remaining 21 patients were markedly higher on the last day of FST in women who completed the test during the luteal phase than in those who completed FST during the follicular phase [1 (1–6) vs 26 (11–42) nmol/l] consistent with ovulation. Importantly, median upright (1000 h) day 4 aldosterone levels were also significantly higher in this group [luteal 600 (222–1600) vs follicular 254 (18–437) pmol/l; P = 0·006]. Aldosterone was significantly (P = 0·01) higher in women studied in the luteal (but not follicular) phase compared to the age-matched (mean age 42 ± 4 years SD) men [278 (59–386) pmol/l].

Figure 1.

Basal and day 4 (a) upright plasma aldosterone levels and (b) upright direct renin concentrations (DRC) in the follicular group, luteal group and males. The group data plots represent median ± interquartile range. *P < 0·05 vs day 4 follicular and males. The horizontal lines represent the cut-off values for normal suppression by day 4 of fludrocortisone suppression testing. DRC levels that were below the lower limit of quantification were rounded up to 2 mU/L.

Median FSH levels were higher (P = 0·02) in patients studied during the follicular phase as expected. There were no significant differences between the phases for median DRC, PRA, LH, cortisol and oestradiol.

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