engleski

Improved performance of attention task in mid- luteal phase of menstrual cycle can be influenced by progesterone, but not estrogen

Numerous studies suggested that sex-hormones could influence cognitive function in women, in lifetime, but inconsistency in their impact during different phases of menstrual cycle (1-3). In addition, results on the role of progesterone are scarce (4). Here we addressed several methodological problems recognized in published studies: a) inappropriate selection of cycle phases, b) a large inter-individual variability in cognitive function, due to non-homogenous groups of subjects which could affect the reliability of results’ interpretation ; and c) measurement of sex hormones concentrations in blood with standardized tests (5). The aim of this study was to exactly determine the phase of cycle and to evaluate the role of sex hormones in modulation of specific cognitive function. Sixteen healthy, normal cycling female medical students aged 22-24 (M = 23 SD = 0.85) volunteered to participate in this study. The study was approved by the Ethical Committee of the Medical School Osijek, Croatia.Cognitive tasks were performed in three different phases of menstrual cycle (EF - early follicular phase, day 2-4 ; O - proven ovulatory phase and ML – mid-luteal phase, 7 – 9 days after ovulation). To appoint the date of ovulation ELISA-based LH urinary strips were used. Hormone levels (E2 - estrogen, P-progesterone, LH and FSH) were assessed from venous blood to confirm menstrual cycle phases. Values are presented as means±SEM, compared by One way ANOVA repeated measures, post hoc Tukey and Holm-Sidac tests, when appropriate (SigmaStat 3.5). Interestingly, all tested women showed above average results in performed tasks for cognitive function evaluation, independently of type of test. The results of hormone levels have shown that the cognitive tasks were done at appropriate points of menstrual cycle. LH and E2 were highest in O phase ; the highest P level in ML phase of cycle (Table 1). There was no significant difference in immediate and delayed recall, implicate or explicate memory and verbal fluency among any phases of menstrual cycle. However, there was significantly better performance in attention task (given as total score) in ML phase (580.38±15.23) compared to the EF (519±19.19) and the O (547.13±16.35) phase of the cycle (p=0.001), with highest P levels, suggesting that attention task performance could be influenced by progesterone. The results in attention task are not related to the changes in E2 levels. Furthermore, there is no enough valid proof for the role of E2 in the modification of cognitive function in women over the length of cycle.

menstrual cycle; estrogen; progesterone; attention; cognition

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