Preserved ovarian reserve in night-active versus day-active women: a cross-sectional comparison of neuroendocrine markers.
4 affiliations
- 1Department of Obstetrics and Gynecology, Cal State Hospital, Denizli, Turkey. [email protected].
- 2Department of Obstetrics and Gynecology, Osmaniye Training and Research Hospital, University of Health Sciences, Osmaniye, Turkey.
- 3Deparment of Obstetrics and Gynecology, Cihanpol Private Hospital, Mardin, Turkey.
- 4Department of Obstetrics and Gynecology, Haseki Training and Research Hospital, University of Health Sciences, Istanbul, Turkey.
Abstract
Background
Shift work inverts the sleep-wake cycle and may perturb circadian-controlled reproductive hormones, yet its effect on ovarian reserve in young women is uncertain, and data on the circadian-sensitive neuropeptides kisspeptin and melatonin are scarce. We compared ovarian reserve and serum kisspeptin, melatonin, and thyroid-stimulating hormone (TSH) between night-active and day-active women.Methods
In this cross-sectional study, 90 healthy women aged 18-35 years with normal body mass index were enrolled (46 night-active, 44 day-active). On cycle day 3, ovarian reserve was assessed by ultrasonography (ovarian volume, antral follicle count [AFC]) and biochemistry (FSH, LH, estradiol, anti-Müllerian hormone [AMH]); prolactin, TSH, vitamin D, kisspeptin, and melatonin were also measured. Groups were compared with distribution-appropriate tests and covariate-adjusted ANCOVA.Results
Ovarian reserve was similar between groups: ovarian volume (p = 0.623), AFC (median 6.0 vs. 6.0, p = 0.791), and AMH (2.7 vs. 3.1 ng/mL, p = 0.862) did not differ, nor did FSH, LH, estradiol, prolactin, or vitamin D (all p > 0.05). Night-active women had higher median kisspeptin (889.5 vs. 336.2 ng/L, p < 0.001), melatonin (699.9 vs. 225.1 ng/L, p < 0.001), and TSH (2.0 vs. 1.5 mU/L, p = 0.020), and shorter sleep duration. The kisspeptin and melatonin differences persisted after covariate adjustment; the TSH difference did not.Conclusion
The primary effect of a night-active circadian rhythm was neuroendocrine rather than gonadal: ovarian reserve was not detectably altered in young, normal-BMI women, while kisspeptin, melatonin, and TSH were higher. These neuroendocrine differences are hypothesis-generating: because the groups were sampled at opposite points of the daily rhythm (~ 21:00 vs. ~ 09:00), they cannot be separated from a time-of-sampling effect and likely reflect circadian state rather than altered hormone output.
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BibTeX
@article{gungor2026preserved,
title = {{Preserved ovarian reserve in night-active versus day-active women: a cross-sectional comparison of neuroendocrine markers.}},
author = {Ezgi Gungor and Kubra Sevim Pehlivan and Aysegul Ciydem and Numan Cim},
journal = {BMC women's health},
year = {2026},
month = sep,
doi = {10.1186/s12905-026-04842-z},
url = {https://europepmc.org/article/MED/42958239},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Preserved ovarian reserve in night-active versus day-active women: a cross-sectional comparison of neuroendocrine markers.
AU - Ezgi Gungor
AU - Kubra Sevim Pehlivan
AU - Aysegul Ciydem
AU - Numan Cim
PY - 2026
DA - 2026/09/02
JO - BMC women's health
DO - 10.1186/s12905-026-04842-z
UR - https://europepmc.org/article/MED/42958239
AB - Background Shift work inverts the sleep-wake cycle and may perturb circadian-controlled reproductive hormones, yet its effect on ovarian reserve in young women is uncertain, and data on the circadian-sensitive neuropeptides kisspeptin and melatonin are scarce. We compared ovarian reserve and serum kisspeptin, melatonin, and thyroid-stimulating hormone (TSH) between night-active and day-active women.Methods In this cross-sectional study, 90 healthy women aged 18-35 years with normal body mass index were enrolled (46 night-active, 44 day-active). On cycle day 3, ovarian reserve was assessed by ultrasonography (ovarian volume, antral follicle count [AFC]) and biochemistry (FSH, LH, estradiol, anti-Müllerian hormone [AMH]); prolactin, TSH, vitamin D, kisspeptin, and melatonin were also measured. Groups were compared with distribution-appropriate tests and covariate-adjusted ANCOVA.Results Ovarian reserve was similar between groups: ovarian volume (p = 0.623), AFC (median 6.0 vs. 6.0, p = 0.791), and AMH (2.7 vs. 3.1 ng/mL, p = 0.862) did not differ, nor did FSH, LH, estradiol, prolactin, or vitamin D (all p > 0.05). Night-active women had higher median kisspeptin (889.5 vs. 336.2 ng/L, p < 0.001), melatonin (699.9 vs. 225.1 ng/L, p < 0.001), and TSH (2.0 vs. 1.5 mU/L, p = 0.020), and shorter sleep duration. The kisspeptin and melatonin differences persisted after covariate adjustment; the TSH difference did not.Conclusion The primary effect of a night-active circadian rhythm was neuroendocrine rather than gonadal: ovarian reserve was not detectably altered in young, normal-BMI women, while kisspeptin, melatonin, and TSH were higher. These neuroendocrine differences are hypothesis-generating: because the groups were sampled at opposite points of the daily rhythm (~ 21:00 vs. ~ 09:00), they cannot be separated from a time-of-sampling effect and likely reflect circadian state rather than altered hormone output.
SN - 1472-6874
ER -