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Evaluation of heart rate variability (HRV) is based on analysis of consecutive R-R intervals and may provide quantitative information on the modulation of cardiac vagal and sympathetic efferent activities. In particular, power spectral analysis as well as the fractal dimension of HRV represent non-invasive measures that reflect brain-heart interaction in different physiopathological conditions. This study was performed to investigate the relationship between autonomic nervous cardiac influence and three phases (menses, follicular phase and luteal phase) of the menstrual cycle. Heart rate (HR) was recorded in 6 eumenorrheic young females, continuously for 20 min, at rest. From the tachograms, fractal dimension, FFT spectra and beta coefficient were evaluated. The components of two spectral bands were calculated: 0.040 Hz - 0.150 Hz (low frequency, LF), and 0.150 Hz - 0.80 Hz (high frequency, HF). The results indicate no correlation between HR and follicular as well as luteal phase of the menstrual cycle. Total power and HF spectral component increase, whereas LF spectral component decreases in the luteal phase compared to the follicular one. The fractal dimension does not show significant differences among the three phases. Beta coefficient decreases during luteal phase in respect of follicular one and menses. In conclusion, these results indicate in healthy young women a correlation between female sex hormones (17 beta-oestradiol, progesterone and pituitary gonadotrophins) concentrations and some HRV parameters with higher HR variability during the luteal phase.

Study Question: Are in vitro maturation (IVM) rates of cumulus-oocyte complexes (COCs), retrieved from breast cancer patients seeking urgent fertility preservation (FP) before neoadjuvant chemotherapy, different between those recovered in the follicular or in the luteal phase of the cycle?Summary Answer: The present investigation reveals no major difference in the number of COCs recovered or their IVM rates whatever the phase of the cycle at which egg retrieval is performed, suggesting that IVM is a promising tool for breast cancer patients seeking urgent oocyte cryopreservation.What Is Known Already: FP now represents a standard of care for young cancer patients having to undergo gonadotoxic treatment. Mature oocyte cryopreservation after IVM of COCs has been proposed for urgent FP, especially in women, who have no time to undergo ovarian stimulation, or when it is contraindicated.Study Design, Size, Duration: From January 2011 to December 2014, we prospectively studied 248 breast cancer patients awaiting neoadjuvant chemotherapy, aged 18-40 years, candidates for oocyte vitrification following IVM, either at the follicular or the luteal phase of the cycle.Participants/materials, Setting, Methods: Serum anti-Müllerian hormone and progesterone levels and antral follicle count (AFC) were measured prior to oocyte retrieval. Patients were sorted into two groups according to the phase of the cycle during which eggs were harvested (Follicular phase group, n = 127 and Luteal phase group, n = 121). Number of COCs recovered, maturation rates after 48 h of culture and total number of oocytes cryopreserved were assessed. Moreover, the oocyte retrieval rate (ORR) was calculated by the number of COCs recovered ×100/AFC.Main Results and the Role Of Chance: In the Follicular and the Luteal phase groups, women were comparable in terms of age, BMI and markers of follicular ovarian status. There was no significant difference in the number of COCs recovered (mean ± SEM), 9.3 ± 0.7 versus 11.1 ± 0.8, and ORR (median (range)) 43.1 (1-100) versus 47.8 (7.7-100)%. Moreover, maturation rates after 48 h of culture (median (range)) were comparable in the follicular and luteal phase groups, 66.7 (20-100) versus 64.5 (0-100)%. Finally, the total number of oocytes cryopreserved (mean ± SEM) was similar in both groups (6.2 ± 0.4 versus 6.8 ± 0.5).Limitations, Reasons For Caution: Despite the intact meiotic competence of immature oocytes recovered during the follicular or the luteal phase, there is a dramatic lack of data regarding the outcome of IVM oocytes cryopreserved in cancer patients.Wider Implications Of the Findings: IVM of oocytes may be an interesting method of FP in urgent situations. Improving the culture conditions will be needed to increase the maturation rates and the overall potential of in vitro matured oocytes.Study Funding/competing Interests: None.Trial Registration Number: N/A. [ABSTRACT FROM AUTHOR]