{
  "abstract": "Background\n\nShift 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\n\nIn 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\n\nOvarian 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\n\nThe 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.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Obstetrics and Gynecology, Cal State Hospital, Denizli, Turkey. ezgi-gungor@outlook.com.",
    "Department of Obstetrics and Gynecology, Osmaniye Training and Research Hospital, University of Health Sciences, Osmaniye, Turkey.",
    "Deparment of Obstetrics and Gynecology, Cihanpol Private Hospital, Mardin, Turkey.",
    "Department of Obstetrics and Gynecology, Haseki Training and Research Hospital, University of Health Sciences, Istanbul, Turkey."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Ezgi Gungor",
      "orcid": "0009-0000-1748-0715"
    },
    {
      "affs": [
        1
      ],
      "name": "Kubra Sevim Pehlivan",
      "orcid": "0009-0007-7185-7000"
    },
    {
      "affs": [
        2
      ],
      "name": "Aysegul Ciydem",
      "orcid": "0009-0002-3107-6756"
    },
    {
      "affs": [
        3
      ],
      "name": "Numan Cim",
      "orcid": "0000-0003-0983-3204"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/979dqdg3b7hmy.bib",
  "cited_by": 0,
  "doi": "10.1186/s12905-026-04842-z",
  "fulltext_url": "https://europepmc.org/articles/PMC13717976",
  "id": "979dqdg3b7hmy",
  "issns": [
    "1472-6874"
  ],
  "landing_url": "https://europepmc.org/article/MED/42958239",
  "language": "eng",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Research"
    ],
    [
      "openalex",
      "2743|Ovarian function and disorders"
    ]
  ],
  "openalex": "W7205012451",
  "pdf_url": "https://europepmc.org/articles/PMC13717976?pdf=render",
  "pmcid": "PMC13717976",
  "pmid": "42958239",
  "published": "2026-09-02",
  "publisher": "BMC",
  "ris": "https://research.draconitic.com/paper/979dqdg3b7hmy.ris",
  "sources": [
    {
      "first_seen": "2026-11-01T00:20:45Z",
      "native_id": "MED:42958239",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42958239"
    },
    {
      "first_seen": "2026-11-02T12:22:09Z",
      "native_id": "PMC13717976",
      "source": "pmc",
      "url": "https://doi.org/10.1186/s12905-026-04842-z"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2743|Ovarian function and disorders",
      "subfield": "reproductive-child"
    }
  ],
  "title": "Preserved ovarian reserve in night-active versus day-active women: a cross-sectional comparison of neuroendocrine markers.",
  "title_text": "Preserved ovarian reserve in night-active versus day-active women: a cross-sectional comparison of neuroendocrine markers.",
  "type": "peer-reviewed",
  "updated_at": "2026-11-02T12:22:09Z",
  "url": "https://research.draconitic.com/paper/979dqdg3b7hmy",
  "venue": "BMC women's health",
  "versions": []
}