Annual and sub-annual rhythms in human conception rates: time-series analyses show annual and weekday but no monthly rhythms in daily counts for last normal menses

Boklage, Charles E.; Zincone, Louis H.; Kirby, Charles F.

doi:10.1093/oxfordjournals.humrep.a137766

Cited by 4 publications

(2 citation statements)

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“…Women and their physicians tend to specify odd numbers and/or multiples of the number 5, like 1, 5, 15, 20, 25, when listing the first day of the LMP (Sutton, 2003). Moreover, U.S. women may associate the date of the LMP to major holidays, like Independence Day (July 4th), Valentines Day (February 14th), New Year's Eve, the week before Christmas, Halloween (October 31st), Thanksgiving (Fourth Thursday of November), Groundhog Day (February 2nd), or Cinco de Mayo (May 5th) (Boklage et al, 1992b). However, these biases are thought to introduce relatively minor error in estimating the week or month of conception in comparison to the amount of error that may occur when estimating the date of conception by subtracting 40 weeks, the standardized gestational length, from the date of assumed term birth.…”

Section: Discussionmentioning

confidence: 99%

Annual Pattern of Human Conception in the State of Texas

Chandwani

Cech

Smolensky

et al. 2004

Chronobiology International

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A total of 2,828,068 State of Texas singleton conceptions, estimated from the date of the first day of the last menstrual period, were assessed for annual periodicity by multiple-component (1-yr fundamental plus the 6- and 3-month harmonics) Cosinor analysis. An annual pattern (p < 0.001) of conception was detected with a December peak, end of July-beginning of August trough and modest amplitude (total peak-to-trough variation) equal to 13.3% of the yearly mean. Annual patterns (p < 0.005) of generally comparable peak and trough times were also documented for conceptions categorized by maternal marital status, age, ethnicity, years of education, birthplace, and county (Texas-Mexico border vs. non-border) of residence. The amplitude, a measure of the prominence of the annual pattern, varied by race (two-fold greater for non-Hispanic Blacks and Hispanics than non-Hispanic Whites), age (50-60% greater for the 19-year-old and younger group than the 20-29 and 30-44-year-old groups) and maternal education (two-fold greater for those with 0-8 than 13 or more years of schooling). Annual patterns (p < 0.001) in conceptions, generally with December peak and end of July-beginning of August trough, were also detected for neonatal variables categorized by birth weight, birth order, gestational age, and gender. The amplitude of the annual pattern in conceptions varied directly with gestational age and inversely with birth weight class.

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Section: Discussionmentioning

confidence: 99%

Annual Pattern of Human Conception in the State of Texas

Chandwani

Cech

Smolensky

et al. 2004

Chronobiology International

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“…Seasonal changes in spontaneous fecundity have been observed in several human populations [1][2][3]. Seasonal patterns have been reported for births [4,5], twin pregnancies [6], stillbirths [7], ectopic pregnancies [8] and spontaneous abortions [7,9,10].…”

Section: Introductionmentioning

confidence: 99%

Seasonality and humanin vitrofertilization outcome

Revelli

Sala²,

Gennarelli

et al. 2005

Gynecological Endocrinology

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Seasonal changes in spontaneous fecundity have been observed in several human populations, but it is not clear whether the same applies to human in vitro fertilization-embryo transfer (IVF) procedures. In the present study, 2067 patients undergoing their first IVF attempt between the years 1998 and 2003 were grouped into four 'seasons' (December-February, March-May, June-August, September-November) according to the day on which they were administered human chorionic gonadotropin. Several parameters known to affect IVF outcome (including ovarian response to gonadotropins, sperm and oocyte quality, fertilization rate, embryo quality, pregnancy and implantation rates) were considered and potential changes among the four seasonal periods were analyzed. Moreover, some confounding variables (sperm quality, age, duration of infertility, indications for IVF) were controlled for. Overall, pregnancy rate per oocyte pick-up and per embryo transfer of 32.5% and 35.8%, respectively, as well as implantation rate of 18.9%, were recorded. None of the observed IVF-related parameters showed any significant change clearly related to a specific seasonal period, their fluctuations throughout the year being randomly determined. Ovarian responsiveness to gonadotropins, quality of gametes and embryos, and fertilization and implantation processes were apparently not significantly affected by seasonality. It is concluded that the results of a good-quality IVF program in humans are not significantly affected by the season of the year in which the IVF attempt is accomplished; therefore, season is not a relevant factor to be considered when planning an IVF treatment.

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Influence of melatonin and photoperiod on animal and human reproduction

Cagnacci¹,

Volpe²

1996

J Endocrinol Invest

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Annual and sub-annual rhythms in human conception rates: time-series analyses show annual and weekday but no monthly rhythms in daily counts for last normal menses

Cited by 4 publications

References 0 publications

Annual Pattern of Human Conception in the State of Texas

Annual Pattern of Human Conception in the State of Texas

Seasonality and humanin vitrofertilization outcome

Influence of melatonin and photoperiod on animal and human reproduction

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