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Cited by 36Reproductive Physiology in LivestockMaternal and Perinatal Health InterventionsAnimal Behavior and Welfare Studies

Lunar Cycle Influences Spontaneous Delivery in Cows

Open access
Yonezawa, Tomohiro, Uchida, Mona, Tomioka, Michiko, Matsuki, Naoaki·2016·PLOS ONE
DOI 10.1371/journal.pone.0161735PMC PMC5006988
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Abstract

There is a popular belief that the lunar cycle influences spontaneous delivery in both humans and cattle. To assess this relationship, we investigated the synodic distribution of spontaneous deliveries in domestic Holstein cows. We used retrospective data from 428 spontaneous, full-term deliveries within a three-year period derived from the calving records of a private farm in Hokkaido, Japan. Spontaneous birth frequency increased uniformly from the new moon to the full moon phase and decreased until the waning crescent phase. There was a statistically significant peak between the waxing gibbous and full moon phases compared with those between the last quarter and the waning crescent. These changes were clearly observed in deliveries among multiparous cows, whereas they were not evident in deliveries among nulliparous cows. These data suggest the utility of dairy cows as models for bio-meteorological studies, and indicate that monitoring lunar phases may facilitate comprehensive understanding of parturition.

AI snapshot

Written from the paper’s full text.

TL;DR

Retrospective calving records from a Hokkaido dairy farm show that spontaneous full-term deliveries in Holstein cows were not uniformly distributed across lunar phases, with a peak around the waxing gibbous-to-full moon period. The pattern was significant among multiparous cows but not nulliparous cows.

Key findings

  • Among 428 spontaneous full-term deliveries, birth frequency increased from new moon to full moon and then decreased toward waning crescent; the overall distribution differed significantly across eight lunar phases (χ² = 15.963, d.f. = 7, p = 0.0255), with a significant peak between waxing gibbous and full moon (p = 0.0006).
  • Multiparous cows showed a significant lunar-phase relationship (χ² = 15.88, d.f. = 7, p = 0.0262), with more deliveries between waxing gibbous and full moon than between last quarter and waning crescent (p = 0.0016); nulliparous cows did not show a significant change (χ² = 5.68, d.f. = 7, p = 0.5781).
  • Differences between actual and predicted delivery dates varied significantly among lunar phases for all cows and multiparous cows; cows predicted to deliver from new moon to first quarter tended to delay, while those predicted from full moon to last quarter tended to deliver when predicted.
  • Weather conditions were not significantly related to delivery timing (χ² = 3.495, d.f. = 3, p = 0.3215), and gaps between actual and predicted delivery dates were not correlated within the same cows (R² = 0.1162, p = 0.5925).

Methods

  • Retrospective analysis of calving records from one private dairy farm in Ishikari, Hokkaido, Japan, from September 1, 2011 to August 31, 2013; included 428 spontaneous, full-term deliveries not induced by parturifacients.
  • Cows were Holstein; mean age was 3.52 years (SD = 1.62), mean gestational age was 283.54 days (SD = 4.04), and predicted delivery date was defined as 284 days after final artificial insemination. Of deliveries, 145 were nulliparous (33.9%) and 283 multiparous (66.1%).
  • Lunar phases were categorized into eight phases based on a 29.53-day lunar month; delivery distributions were compared using χ² tests with Ryan-Holm step-down Bonferroni multiple comparisons, and actual-versus-predicted delivery date gaps were compared using Kruskal-Wallis and Steel-Dwass tests, with p < 0.05 considered significant.

Limitations

  • The paper states that the relatively small sample size made it difficult to draw definitive conclusions, and that results cannot be extrapolated directly to humans because reproductive physiology can differ between species.
  • The paper notes that light intensities in the free stall and barn were not measured, and that data on estrus incidence, total number of artificial inseminations, and artificial insemination success rate were not collected.
  • Evident from the text: the study is retrospective and from a single farm over three years/25 lunar cycles, and dystocia in primiparous cows may obscure lunar-phase effects in nulliparous deliveries.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1371/journal.pone.0161735

Cites

Statistics

Nothing to recompute.

Claims the paper makes

0 of 13 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Among all spontaneous deliveries, the distribution of deliveries across the eight lunar phases was significantly non-uniform (χ2 = 15.963, d.f. = 7, p = 0.0255).

    “The results of the χ2 test (χ2 = 15.963, d.f. = 7, p = 0.0255) warranted rejection of the null hypothesis”
    Quote in the paperSubstantial claim
  • Findingown data

    There was a clear and significant relationship between delivery timing among multiparous cows and the lunar cycle (χ2 = 15.88, d.f. = 7, p = 0.0262).

    “In contrast, there was a clear and significant relationship between delivery timing among multiparous cows and the lunar cycle (χ2 = 15.88, d.f. = 7, p = 0.0262, Fig 1C).”
    Quote in the paperSubstantial claim
  • Findingown data

    When the lunar cycle was separated into four phases, a significant alteration in delivery distribution was observed (χ2 = 10.88, d.f. = 3, p = 0.0124).

    “When the lunar cycle was separated into four phases, a significant alteration was observed (Fig 3A).”
    • Also stated in: § Results · plain
      “(a) The lunar cycle separated into four phases (χ2 = 10.88, d.f. = 3, p = 0.0124).”
    Quote in the paperSubstantial claim
  • Findingown data

    Delivery timing among nulliparous cows did not significantly change throughout the lunar cycle (χ2 = 5.68, d.f. = 7, p = 0.5781).

    “Delivery timing among nulliparous cows did not significantly change throughout the lunar cycle, although it exhibited a tendency to increase between the waxing gibbous and full moon phases (χ2 = 5.68, d.f. = 7, p = 0.5781, Fig 1B).”
    Quote in the paperSubstantial claim
  • Findingown data

    There was no significant relationship between weather conditions and delivery timing (χ2 = 3.495, d.f. = 3, p = 0.3215).

    “There was no significant relationship between weather conditions and delivery timing (χ2 = 3.495, d.f. = 3, p = 0.3215).”
    Quote in the paperNot a substantial claim
  • May combine two claims. 9
  • The quote only partly states this claim. 1
  • Classified as probably not a substantial claim. 8

  • May combine two claims.

    Findingown data

    Spontaneous birth frequency in domestic Holstein cows increased uniformly from the new moon to the full moon phase and decreased until the waning crescent phase.

    “Spontaneous birth frequency increased uniformly from the new moon to the full moon phase and decreased until the waning crescent phase.”
    • Also stated in: § Results · plain
      “Among all spontaneous deliveries, birth frequency increased uniformly from the new moon to the full moon phase, and then decreased until the waning crescent (Fig 1A).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The numbers of days between predicted and actual delivery dates differed significantly among the eight moon phases for all cows and for multiparous cows.

    “In further analyses, the numbers of days between predicted and actual delivery dates differed significantly among the eight moon phases for all cows, and for multiparous cows (Fig 2).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Cows with predicted delivery dates during the new moon to first quarter phase tended to delay delivery, whereas those with predicted delivery dates during the full moon to last quarter phase tended to deliver when predicted.

    “Specifically, cows with predicted delivery dates during the new moon to first quarter phase tended to delay delivery, whereas those with predicted delivery dates during the full moon to last quarter phase tended to deliver when predicted.”
    Quote in the paperSubstantial claim

  • May combine two claims. The quote only partly states this claim.

    Findingown data

    When the lunar cycle was separated into 16 phases, no significant difference was observed, although a peak in deliveries was observed around the full moon phase (χ2 = 24.86, d.f. = 15, p = 0.0519).

    “However, when it was separated into 16 phases, no significant difference was observed, although a peak in deliveries was observed around the full moon phase (Fig 3B).”
    • Also stated in: § Results · plain
      “(b) The lunar cycle separated into 16 phases (χ2 = 24.86, d.f. = 15, p = 0.0519).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    The dairy cow may be a good model for bio-meteorological study, and monitoring lunar phases provides considerable information for understanding influences on delivery more comprehensively.

    “These data suggest the utility of dairy cows as models for bio-meteorological studies, and indicate that monitoring lunar phases may facilitate comprehensive understanding of parturition.”
    • Also stated in: § Discussion · hedged
      “These results suggest that the dairy cow may be a good model for bio-meteorological study, and that monitoring lunar phases provides considerable information for understanding the influences on delivery more comprehensively.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Two studies from the USA, one from Germany, and one from Brazil showed no lunar influence on hospital admissions for labor.

    “Two studies from the USA [11, 12], one from Germany [16], and one from Brazil [3] showed no lunar influence on hospital admissions for labor.”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [11] S Morton-Pradhan, 2005, Birth rate and its correlation with the lunar cycle and specific atmospheric conditions, Am J Obstet Gynecol source

      Not checked in the free run.

    • cites [12] JM Arliss, 2005, The effect of the lunar cycle on frequency of births and birth complications, Am J Obstet Gynecol source

      Not checked in the free run.

    • cites [16] O Kuss, 2008, Lunar cycle and the number of births: a spectral analysis of 4,071,669 births from South-Western Germany, Acta Obstet Gyn Scan source

      Not checked in the free run.

    • cites [3] AM Ochiai, 2012, Atmospheric conditions, lunar phases, and childbirth: a multivariate analysis, Int J Biometeorol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Obesity affects the length of gestation.

    “For instance, obesity affects the length of gestation [17], weekends tend to yield reduced childbirth frequency, and there are peaks in labor admission rates on Mondays and Fridays [3].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [17] S Carlhäll, 2013, Maternal body mass index and duration of labor, Eur J Obstet Gynecol Reprod Biol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Weekends tend to yield reduced childbirth frequency, and there are peaks in labor admission rates on Mondays and Fridays.

    “For instance, obesity affects the length of gestation [17], weekends tend to yield reduced childbirth frequency, and there are peaks in labor admission rates on Mondays and Fridays [3].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] AM Ochiai, 2012, Atmospheric conditions, lunar phases, and childbirth: a multivariate analysis, Int J Biometeorol source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Dystocia is a widely accepted risk during first parturition in cows, reflecting smaller sizes and weights of younger primiparous dams.

    “In addition, dystocia is a widely accepted risk during first parturition in cows, reflecting smaller sizes and weights of younger primiparous dams [18].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [18] M Sieber, 1989, Effects of body measurements and weight on calf size and calving difficulty of Holsteins, J Dairy Sci source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    Data on the incidence rate of estrus, total number of AIs performed, and success rate of AIs were not collected in the present study.

    “However, it would be difficult to perform a detailed evaluation because data on the incidence rate of estrus, total number of AIs performed, and success rate of AIs were not collected in the present study.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    The present results cannot be extrapolated directly to humans because reproductive physiology can be quite different between species.

    “Nevertheless, the present results cannot be extrapolated directly to humans because reproductive physiology can be quite different between species.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Weather patterns, such as changes in atmospheric pressure and temperature, affect timing of birth in cattle.

    “Weather patterns, such as changes in atmospheric pressure and temperature, have been reported to affect timing of birth in cattle [15], which is consistent with comparable reports for humans [1–3].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [15] TR Troxel, 2012, Relationships of barometric pressure and environmental temperature with incidence of parturition in beef cows, J Anim Sci source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Various factors could influence birth frequency in humans, which could mask the influence of the lunar phase.

    “However, various factors could influence birth frequency in humans, which could mask the influence of the lunar phase.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [17] S Carlhäll, 2013, Maternal body mass index and duration of labor, Eur J Obstet Gynecol Reprod Biol source

      Not checked in the free run.

    • cites [3] AM Ochiai, 2012, Atmospheric conditions, lunar phases, and childbirth: a multivariate analysis, Int J Biometeorol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Ghiandoni et al. reported a higher rate of childbirth in Italy during the full moon phase, but claimed the association was too weak to predict the days with the highest frequency of deliveries.

    “Although Ghiandoni et al. reported a higher rate of childbirth in Italy during the full moon phase [13], they also claimed that the association was too weak to predict the days with the highest frequency of deliveries.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] G Ghiandoni, 1998, Does lunar position influence the time of delivery? A statistical analysis, Eur J Obstet Gynecol Reprod Biol source

      Not checked in the free run.

14 of 14

  • The paper relies on this without support.

    The insemination and parturition records of cattle are accurate in comparison with human memory.

    “The insemination and parturition records of cattle are accurate in comparison with human memory.”
1 of 1

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • In many marine species and some terrestrial species, reproductive behavior is synchronized with a particular phase of the lunar cycle.

    “In many marine species (1–5) and some terrestrial species (6–9), reproductive behavior is synchronized with a particular phase of the lunar cycle (often full or new moon).”

    From Women temporarily synchronize their menstrual cycles with the luminance and gravimetric cycles of the Moon (2021) · cites this paper as [9]

  • The resulting changes in gestation length in Holstein cows are less than 1% (average: 284 days).

    “The resulting changes are less than 1% in gestation length (average: 284 days)”

    From An Overview of Monthly Rhythms and Clocks (2017) · cites this paper as [65]

  • There was a significant effect of the moon phase in delaying (new moon) or accelerating (full moon to waning gibbous phase) the actual delivery for up to 2 days in Holstein cows.

    “Specifically, there was a significant effect of the moon phase in delaying (new moon) or accelerating (full moon to waning gibbous phase) the actual delivery for up to 2 days (65).”

    From An Overview of Monthly Rhythms and Clocks (2017) · cites this paper as [65]

  • In a systematic, 3-year study on over 400 Holstein cows, Yonezawa and colleagues reported a significant influence of the moon phase on spontaneous delivery dates, with deliveries peaking shortly before the full moon, while being minimal around new moon.

    “In a systematic, 3-year study on over 400 Holstein cows raised on a Japanese farm, Yonezawa and colleagues recently reported a significant influence of the moon phase on spontaneous delivery dates, with deliveries peaking shortly before the full moon, while being minimal around new moon (65).”

    From An Overview of Monthly Rhythms and Clocks (2017) · cites this paper as [65]

  • The observed pattern in Holstein cows was not generated by a fluctuation of conception frequencies.

    “As the animals were artificially inseminated, and the insemination dates were accurately recorded for each cow, the authors were able to show that the observed pattern was not generated by a fluctuation of conception frequencies.”

    From An Overview of Monthly Rhythms and Clocks (2017) · cites this paper as [65]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Two-year interval described as three years

    Minor

    September 1, 2011 through August 31, 2013 spans two years, not three.

  • Lunar phase interval named in reverse order

    Minor

    The Results name a "waning crescent to last quarter" phase, but the Methods define that interval in the opposite order.

2 of 2

The citation lists haven’t been fetched yet

References 22 · Cited by 36

Research works printed but not linked: 2

  1. P Leonard, 1987, Childbirths and the full moon, The Doings, 20, 7
  2. E Miyaoka, 1989, Application of mixed Poisson-process models to some Canadian data, Ca J Stat, 17, 123

Authors
Yonezawa, T., Uchida, M., Tomioka, M., & Matsuki, N.
Affiliations
  • The University of Tokyo (JP)
  • Kitasato University (JP)
Corresponding author
Yonezawa, Tomohiro
ORCID
Venue
PLOS ONE
Publisher
Public Library of Science (PLoS)
Published
2016-08-31
Volume
11
Issue
8
Pages
e0161735
ISSN
1932-6203 (ISSN-L)
DOI
10.1371/journal.pone.0161735
PMC
PMC5006988
OpenAlex
W2512843223
Semantic Scholar
472591520bf373b6b2ccb59f8bb91dbe0ccf201d
Cited by
36
References
22
Citations by year
2026: 3 · 2025: 7 · 2024: 4 · 2023: 5 · 2022: 3 · 2021: 4 · 2020: 3 · 2019: 3 · 2018: 3 · 2017: 1
FWCI
4.77
Type
journal article
Language
en
Open access
Licence
Locations
  • PLoS ONE (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Institutional Repositories DataBase (IRDB) (submittedVersion, other-oa)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • Figshare (submittedVersion, cc-by)
Funders
Japan Society for the Promotion of Science (15KK0275, 15H04590, 16K15045)
Topics
  • Life Sciences › Agricultural and Biological Sciences › Agronomy and Crop Science › Reproductive Physiology in Livestock
  • Health Sciences › Medicine › Obstetrics and Gynecology › Maternal and Perinatal Health Interventions
  • Health Sciences › Veterinary › Small Animals › Animal Behavior and Welfare Studies
Keywords
lunar cycle, spontaneous delivery, childbirth, Holstein cows, dairy cattle, lunar phases, multiparous cows
MeSH terms
Animals, Cattle, Female, Parity, Pregnancy, Moon, Parturition

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