Effects of the menstrual and oral contraceptive cycle phases on microvascular reperfusion

Abstract

The objective was to examine whether the menstrual or monophasic oral contraceptive cycle phases affect microvascular responsiveness of the lower limb in healthy, active women. During the follicular or inactive-pill phase and the luteal or active-pill phase of the menstrual or oral contraceptive cycle, respectively, 15 non-oral contraceptive users (mean ± SD; 27 ± 6 years of age) and 15 monophasic oral contraceptive users (24 ± 4 years of age) underwent a lower-limb vascular occlusion test (5 min baseline, 5 min occlusion and 8 min post cuff release). Menstrual cycle phases were verified using an ovulation test. Vascular responsiveness was assessed by calculating the near-infrared spectroscopy-derived muscle oxygen saturation (StO 2) reperfusion slope (slope 2 StO 2) and the post occlusion StO 2 area under the curve (StO 2AUC) of the tibialis anterior muscle. There were no differences in the reperfusion slope (as a percentage per second; follicular, 1.18 ± 0.48; luteal, 1.05 ± 0.48, inactive-pill, 0.95 ± 0.23; and active-pill, 0.87 ± 0.36; P = 0.09) and area under the curve (as a product of the percentage and seconds; follicular, 1067 ± 562; luteal, 918 ± 414, inactive-pill, 945 ± 702; and active-pill, 750 ± 519; P = 0.09) between the phases of the menstrual or oral contraceptive cycle, regardless of pill generation. The duration of oral contraceptive use was not associated with changes in slope 2 StO 2 (r = 0.02, P = 0.94) or StO 2AUC (r = −0.34, P = 0.22) between cycle phases. In conclusion, vascular responsiveness remained unchanged between the early follicular and mid-luteal phases of the menstrual cycle and the inactive-pill and active-pill phases of the oral contraceptive cycle.

Suitability of the muscle O2 resaturation parameters most used for assessing reactive hyperemia: a near-infrared spectroscopy study

“… 3 The majority of StO 2 parameters adopted in previous studies include reperfusion rate (i.e., upslope of the StO 2 signal during the initial 10 s and 30 s, and until the StO 2 signal reaches baseline values), 11 - 13 magnitude of reperfusion (i.e., total area under the curve [AUC] of StO 2 and the difference between the lowest and highest StO 2 value), 4 , 13 - 17 and others (e.g., time to StO 2 baseline, time to StO 2 maximum, and AUC above the baseline). 13 , 15 , 18 , 19 …”

Young healthy adults with a family history of hypertension have increased microvascular reactivity but decreased macrovascular function

“…As this study was not designed to focus on sex or hormonal influences; controlling for menstrual cycle phase is likely unwarranted. Furthermore, recent evidence suggests that NIRS reperfusion is not effected by menstrual cycle phase 61 …”

“…Furthermore, recent evidence suggests that NIRS reperfusion is not effected by menstrual cycle phase. 61…”

Responders and non‐responders to aerobic exercise training: beyond the evaluation of

“…Although we did not perform a crossover design, we took the following precautions to overcome this limitation: (i) the ROPE + HDI decision-making strategy used has a considerable advantage over null-hypothesis testing and magnitude-based inference, such that statistical inferences are made through Bayesian credible intervals (Kruschke, 2018;Sainani, 2018); (ii) V O 2max assessment is subject to random within-subject and day-to-day variation, and for this reason, we considered a coefficient of variation of 5.6% around each individual ΔVO 2max , as suggested elsewhere (Hecksteden et al, 2018), and (iii) we used a conservative value of 20% (the recommended value is 10%) of the pre-training standard deviation as the minimal clinical relevant change in V O 2max around the null value (i.e., zero), which then the percentage of the Bayesian credible interval within this region was calculated (Maturana et al,). Additionally, although recent evidence shows that phase of the menstrual cycle does not seem to have an effect on submaximal and maximal outcomes, as well as on microvascular measures (Mattu et al, 2020;Williams et al, 2020), it should be acknowledged that our sample had an imbalanced number of males (N = 12) and females (N = 30).…”

“…Males and females aged between 20 and 40 years old were recruited for the study. It should be noted that even though the phase of the menstrual cycle status within which testing occurred was not controlled in this study, this was not a major consideration in our design as there is compelling evidence showing that the phase of the menstrual cycle does not seem to have an effect on submaximal and maximal outcomes, as well as on microvascular measures (Mattu et al, 2020;Williams et al, 2020). Further inclusion criteria may be found elsewhere (Thiel et al, 2020).…”