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Updated: Mar 7, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures
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Birth and death: Evidence for the same biologic clock.

Mark Phillippe1, Shiela M Phillippe1

  • 1Vincent Center for Reproductive Biology, Department of Obstetrics and Gynecology, Harvard Medical School, Boston, MA, USA.

American Journal of Reproductive Immunology (New York, N.Y. : 1989)
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Telomere shortening in the placenta and fetal membranes may act as a gestational clock, triggering inflammation and birth. This process mirrors aging mechanisms seen in mammals.

Keywords:
biologic clockfetal cell-free DNAparturitiontelomerestrophoblast apoptosis

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Area of Science:

  • Reproductive biology
  • Cellular aging
  • Mammalian physiology

Background:

  • A correlation exists between mammalian lifespan and gestation length, suggesting shared biological clock mechanisms.
  • Telomere shortening, driven by oxidative stress and DNA replication, is a key factor in organismal aging and senescence.
  • The placenta and fetal membranes undergo aging during gestation, culminating in senescence and apoptosis at term.

Purpose of the Study:

  • To propose and review evidence for the "telomere gestational clock" hypothesis.
  • To explore the role of telomere shortening in gestational tissues in parturition.

Main Methods:

  • Review of existing scientific literature and evidence supporting the telomere gestational clock hypothesis.
  • Analysis of biochemical and cellular phenomena in placental and fetal membrane aging.

Main Results:

  • Progressive telomere shortening in gestational tissues (placenta, fetal membranes) leads to cellular aging and apoptosis.
  • Apoptotic death of these tissues releases fetal cell-free DNA.
  • Fetal cell-free DNA acts as an inflammatory mediator, initiating the parturition signaling cascade.

Conclusions:

  • The telomere gestational clock hypothesis provides a framework for understanding parturition.
  • Telomere dynamics in the placenta and fetal membranes are crucial for initiating labor.
  • This mechanism links cellular aging processes to reproductive events.