Birth rate and its correlation with the lunar cycle and specific atmospheric conditions


      This study was undertaken to use the Arizona State birth certificate database for Phoenix metropolitan hospitals, in conjunction with National Weather Service records to determine whether there is a relationship between birth rate and meteorologic or lunar conditions. This study attempts to dispel or lend significance to beliefs among hospital staff that the phase of the moon and/or meteorologic conditions are related to birth rate.

      Study design

      Birth records were limited to spontaneous vaginal deliveries, 37 to 40 weeks' gestation, in Phoenix, between 1995 and 2000 (n = 167,956). Daily birth counts were merged with daily surface weather statistics from the National Weather Service for Sky Harbor Airport, and records of lunar phase for the same period.


      The analyses revealed no significant correlates of birth rate.


      Although there exists a popular belief that the phase of the lunar cycle and weather conditions affect birth rate, no such evidence was found in this study.

      Key words

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        • Kollerstrom N.
        • Staudenmaier G.
        Evidence for lunar sidereal rhythms in crop yeild: a review.
        Biol Agriculture Horticulture. 2001; 19: 247-259
        • Steiger B.
        Werewolf book: the encyclopedia of shape shifting beings.
        Visible Ink Press, Canton (MI)1999
        • Abell G.O.
        • Greenspan B.
        Human births and the phase of the moon.
        N Engl J Med. 1979; 300: 96
        • Marks J.
        • Church C.K.
        • Benrubi G.
        Effects of barometric pressure and lunar phases on premature rupture of the membranes.
        J Reprod Med. 1983; 28: 485-488
        • Witter F.R.
        The influence of the moon on deliveries.
        Am J Obstet Gynecol. 1983; 145: 637-639
        • Joshi R.
        • Bharadwaj A.
        • Gallousis S.
        • Matthews R.
        Labor ward workload waxes and wanes with the lunar cycle, myth or reality?.
        Prim Care Update Ob Gyns. 1998; 5: 184
        • McGregor G.R.
        The meteorological sensitivity of ischaemic heart disease mortality events in Birmingham, UK.
        Int J Biometeorol. 2001; 45: 133-142
        • Makie T.
        • Harada M.
        • Kinukawa N.
        • Toyoshiba H.
        • Yamanaka T.
        • Nakamura T.
        • et al.
        Association of meteorological and day-of-the-week factors with emergency hospital admissions in Fukuoka, Japan.
        Int J Biometeorol. 2002; 46: 38-41
        • Trapasso L.M.
        • Kinkel B.
        Barometric pressure: trigger mechanism in human childbirth.
        Department of Geography and Geology, Indiana State University, Terre Haute (IN)1986 (p. 37-46)
      1. Weatherfor active lives: labor and birth index, 2004. Available at: Accessed on 13 August 2004.

        • Cesario S.K.
        The “Christmas effect” and other biometeorologic influences on childbearing and the health of women.
        J Obstet Gynecol Neonatal Nurs. 2002; 31: 526-535
        • Ahn A.
        • Nallamothu B.K.
        • Saint S.
        “We're jinxed”—are residents' fears of being jinxed during an on-call day founded?.
        Am J Med. 2002; 112: 504