Seasonal patterns of conception in New York City.

Erhardt, Carl L.; Nelson, Frieda; Pakter, Jean

doi:10.2105/ajph.61.11.2246

Cited by 33 publications

(11 citation statements)

References 7 publications

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“…Our cohort witnessed the highest presentation of penile trauma due to coitus in December. This corresponds with peak rates of conception, which have also been noted during the winter months, especially December (Erhardt et al, 1971;Tita et al, 2001). We have not otherwise found reason for this variation.…”

Section: Discussionsupporting

confidence: 69%

Acute penile trauma and associated morbidity: 9-year experience at a tertiary care center

2015

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Section: Discussionsupporting

confidence: 69%

Acute penile trauma and associated morbidity: 9-year experience at a tertiary care center

2015

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“…In the northern hemisphere, birth rates are usually high in the spring months [1]–[3], which has been thought to be related to higher conception rates in the summer to autumn months [2], [4]. In relation to this, patterns have also been documented in health and developmental outcomes of children in association with months of birth.…”

Section: Introductionmentioning

confidence: 99%

Seasonal Variations of Neuromotor Development By 14 Months of Age: Hamamatsu Birth Cohort for Mothers and Children (HBC Study)

et al. 2012

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The present study aimed at investigating whether neuromotor development, from birth to 14 months of age, shows seasonal, cyclic patterns in association with months of birth. Study participants were 742 infants enrolled in the Hamamatsu Birth Cohort (HBC) Study and followed-up from birth to the 14th month of age. Gross motor skills were assessed at the ages of 6, 10, and 14 months, using Mullen Scales of Early Learning. The score at each assessment was regressed onto a trigonometric function of months of birth, with an adjustment for potential confounders. Gross motor scores at the 6th and 10th months showed significant 1-year-cycle variations, peaking among March- and April-born infants, and among February-born infants, respectively. Changes in gross motor scores between the 10th and 14th months also showed a cyclic variation, peaking among July- and August-born infants. Due to this complementary effect, gross motor scores at the 14th month did not show seasonality. Neuromotor development showed cyclic seasonality during the first year of life. The effects brought about by month of birth disappeared around 1 year of age, and warmer months seemed to accelerate the neuromotor development.

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“…In any case, it is difficult to decide whether illegitimate conceptions lead to prompt and honor-saving marriages or whether marriages with subsequent prompt conceptions lead to an increased birth rate 9 months later. The annual distribution of marriages (Erhardt et al, 1971) correlates only weakly with the distribution of firstborn children 9 to 15 months later (Waggoner and Schlacter, 1959); the highest correlations are found for the lag of 14 months. In contrast, Whelpton et al (1966) claim that conceptions occur most frequently in the first month of marriage.…”

Section: Basis For the Rhythmicitymentioning

confidence: 99%

Annual Rhythm of Human Reproduction: I. Biology, Sociology, or Both?

1990

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The annual rhythm of human reproduction was analyzed on the basis of more than 3000 years of monthly birth rates covering 166 regions of the globe. The following variables were used to characterize the annual rhythm of human conception (birth minus 9 months): amplitude, phase of maximum and minimum, phase and length of the time span when rates are above the annual mean (alpha), and the steepest upward slope (delta max) of the curve fitted to the rates. The waveform of the annual rhythm is characteristic for geographical regions (e.g., unimodal or bimodal) and persists as such for many years. In most countries, the onset of alpha coincides with delta max and lies close to the spring equinox. This phase of the rhythm is the most stable over time. In many populations, the rhythm has changed in recent years, specifically in amplitude and phase. The phase of the rhythm depends on latitude, with a 6-month difference between the Northern and Southern Hemispheres. The latitudinal distribution of amplitudes is less systematic. In spite of the many social influences on timing of conceptions, we conclude that the seasonal component in human reproduction is based on biological factors.

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Seasonal patterns of conception in New York City.

Cited by 33 publications

References 7 publications

Acute penile trauma and associated morbidity: 9-year experience at a tertiary care center

Acute penile trauma and associated morbidity: 9-year experience at a tertiary care center

Seasonal Variations of Neuromotor Development By 14 Months of Age: Hamamatsu Birth Cohort for Mothers and Children (HBC Study)

Annual Rhythm of Human Reproduction: I. Biology, Sociology, or Both?

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