Seasonality Of Birth Research Articles

Shifts in peak month of births and socio-economic factors: a study of divided and reunified Germany 1950-2022.

The seasonality of conception and birth has intrigued scientists for over 200 years. Since the 1970s, peak birth months in the northern hemisphere have shifted from early spring to late summer, influenced by oral contraceptives and socio-economic factors. The division of Germany from the end of World War II until reunification in 1990 offers a unique opportunity to analyze these influences while both regions had equal access to contraception. This study aims to identify differences in fertility trends and peak birth months between West and East Germany before and after reunification, considering political, socio-economic factors, and contraceptive availability. A population-based study analyzed overall fertility rates, monthly birth data, peak birth months, and average maternal ages from 1950 to 2022. Fertility patterns were similar in both regions until 1970, showing a sharp increase post-1955 followed by a decline around 1965, likely due to contraception. From 1970 to 1990, East German fertility increased while West Germany's remained lower. After reunification, East German fertility fell sharply but later rose to West German levels. The peak birth month shifted from March to August in West Germany by the mid-1980s, while East Germany experienced this change 20 years later, post-reunification. The 20-year delay in East Germany's shift suggests that oral contraception's impact was influenced by other factors, particularly the age of women at childbirth. Increased control over fertility in the West allowed for more choice in conception timing, a trend adopted in the East after gaining similar autonomy.

An epidemiological study of season of birth, mental health, and neuroimaging in the UK Biobank.

Environmental exposures during the perinatal period are known to have a long-term effect on adult physical and mental health. One such influential environmental exposure is the time of year of birth which affects the amount of daylight, nutrients, and viral load that an individual is exposed to within this key developmental period. Here, we investigate associations between season of birth (seasonality), four mental health traits (n = 137,588) and multi-modal neuroimaging measures (n = 33,212) within the UK Biobank. Summer births were associated with probable recurrent Major Depressive Disorder (β = 0.026, pcorr = 0.028) and greater mean cortical thickness in temporal and occipital lobes (β = 0.013 to 0.014, pcorr<0.05). Winter births were associated with greater white matter integrity globally, in the association fibers, thalamic radiations, and six individual tracts (β = -0.013 to -0.022, pcorr<0.05). Results of sensitivity analyses adjusting for birth weight were similar, with an additional association between winter birth and white matter microstructure in the forceps minor and between summer births, greater cingulate thickness and amygdala volume. Further analyses revealed associations between probable depressive phenotypes and a range of neuroimaging measures but a paucity of interactions with seasonality. Our results suggest that seasonality of birth may affect later-life brain structure and play a role in lifetime recurrent Major Depressive Disorder. Due to the small effect sizes observed, and the lack of associations with other mental health traits, further research is required to validate birth season effects in the context of different latitudes, and by co-examining genetic and epigenetic measures to reveal informative biological pathways.

RELATION OF THE CHARACTERISTICS OF THE MAGNETIC RESONANCE PROFILE OF THE BRAIN IN CHILDREN WITH EPILEPSY ON THE SEASON OF THEIR BIRTH

Purpose of the study. Identifying common and distinctive features of the relationship between the season of children birth and the risk of developing epilepsy and without brain pathologies according to magnetic resonans imaging (MRI) data. Materials and methods of research. 94 children aged 4 to 14 years with a confirmed diagnosis of epilepsy were under observation. The children were divided into two groups: children with brain pathologies according to MRI data and children without brain pathologies according to MRI data. The entire population and the children in these groups are distributed according to their birth months. The proportions of children in each month and season were compared using pairwise tests. A statistically significant difference was considered at t≥1.96 (p≤0.05). Results. In the total population, the smallest and largest proportion of children were born in January and July, respectively (5.2±2.3 and 13.6±3.5%; t=1.98). In the group of children with epilepsy without brain pathology, according to MRI data, the smallest proportion of children were born in May (3.55±2.08%), and the largest in July (12.16±3.64%) and December (12.16±3.64%; t=2.03; p&lt;0.05). Conclusions. MRI can detect brain pathologies in 13.83±3.56% of children with epilepsy. The seasonality of the children birth with epilepsy with and without brain pathologies is different; it is more pronounced in children with epilepsy without brain pathologies according to MRI data.

Seasonality of presentation and birth in catatonia

BackgroundCatatonia is a neuropsychiatric syndrome associated with both psychiatric disorders and medical conditions. Understanding of the pathophysiology of catatonia remains limited, and the role of the environment is unclear. Although seasonal variations have been shown for many of the disorders underlying catatonia, the seasonality of this syndrome has not yet been adequately explored. MethodsClinical records were screened to identify a cohort of patients suffering from catatonia and a control group of psychiatric inpatients, from 2007 to 2016 in South London. In a cohort study, the seasonality of presentation was explored fitting regression models with harmonic terms, while the effect of season of birth on subsequent development of catatonia was analyzed using regression models for count data. In a case-control study, the association between month of birth and catatonia was studied fitting logistic regression models. ResultsIn total, 955 patients suffering from catatonia and 23,409 controls were included. The number of catatonic episodes increased during winter, with a peak in February. Similarly, an increasing number of cases was observed during summer, with a second peak in August. However, no evidence for an association between month of birth and catatonia was found. ConclusionsThe presentation of catatonia showed seasonal variation in accordance with patterns described for many of the disorders underlying catatonia, such as mood disorders and infections. We found no evidence for an association between season of birth and risk of developing catatonia. This may imply that recent triggers may underpin catatonia, rather than distal events.

Seasonality of Births and Marriages among Bessarabian Bulgarians in the 19th and Early 20th Centuries

The article looks at the seasonality of birth and marriage rates among the Bulgarian population in Bessarabia in the nineteenth – early twentieth centuries. The authors argue that the transition from traditional to modern models of reproduction is accompanied by a transformation in the religious identity of Bulgarians. The work demonstrates that starting a family with children becomes more secular and not as dependent on the practices of the church calendar taboos. The main determinants of marriage and birth seasonality are the mechanisms of migration and further adaptation to new conditions. The calculations reveal the levelling and relative uniformity in the distribution of births through the months of the year. These trends highlight the transition from the traditional to the modern model. The dependence on religious factors is gradually weakening while the agricultural work cycle becomes dominant. It evidences the pronounced secularization of the worldview and social practices.

10 Impact of the month of birth on the development of juvenile idiopathic arthritis among Tunisian children

BackgroundJuvenile idiopathic arthritis (JIA) is the most common inflammatory disease influenced by genetic as well as environmental factors. Prior studies from Israel and USA suggested that JIA had a seasonality of birth, with birth peaking in winter and especially in January.ObjectivesThe aim of the study was to evaluate the impact of month of birth and season, and the onset of JIA in Tunisian children.MethodsWe conducted a case-control study including 27 children with JIA compared with a homogeneous control group of 27 children hospitalized in a pediatric orthopedic unit for traumatic reasons and healthy for any chronic inflammatory rheumatism. Statistical differences between groups were also analyzed by non-parametrical tests.ResultsFifty-four patients (25 females and 29 males) were enrolled. The mean age was 11.04 ± 5.58 years and the mean duration of the diseases was 5.29 ± 3,18 years. The frequency of each JIA subset was at follows: polyarticular rheumatoid factor positive (n = 2), polyarticular rheumatoid factor negative (n = 5), psoriatic arthritis (n = 1), enthesitis-related arthritis (n = 11) and oligoarthritis (n = 8). Although the majority of children with JIA were born in November (22.2%) and December (18.5%), there was no significant difference in month of birth distribution between the cases and the controls. Likewise, there was no significant correlation between season of birth and the onset of the disease (p = 0,6).ConclusionThis study didn’t show any correlation between season and month birth, and the onset of JIA. Our result may be explained by the weather in Tunisia which is relatively warm with little variation in temperature between seasons compared with the country where they found a significant correlation. It also may be due to the limited number of our cases.

Risk factors of deficit and non-deficit schizophrenia: Results from a cross-sectional study

AimIt has been observed that deficit and non-deficit schizophrenia (SCZ-D and SCZ-ND) might be characterized by different risk factors. Therefore, the present study aimed to assess as to whether previously reported risk factors of schizophrenia are specifically associated with SCZ-D and SCZ-ND. MethodThis study was based on a cohort of 118 stable outpatients with schizophrenia. A diagnosis of SCZ-D was established using the Schedule for the Deficit Syndrome (SDS). Risk factors were recorded using structured interview, the Operational Criteria for Psychotic Illness (OPCRIT) checklist and the Traumatic Experience Checklist (TEC). The following risk factors were explored: male sex, a history of schizophrenia in first-degree relatives, seasonality of birth, birth weight <3000g, delivery by cesarean section, a history of childhood trauma (emotional abuse, emotional neglect, physical abuse and sexual abuse) as well as substance abuse (other than nicotine) and cigarette smoking at psychosis onset. ResultsIndividuals with SCZ-D were more likely to be males as well as reported higher rates of birth weight <3000g and any categories of childhood trauma. In turn, substance abuse (other than nicotine) at psychosis onset was significantly more frequent in patients with SCZ-ND. Binary logistic regression, controlling for multiple comparisons, revealed similar findings, except for the association with any categories of childhood trauma that appeared to be not significant. ConclusionOur findings partially replicate differential patterns of risk factors for SCZ-D (male sex and birth weight <3000g) and SCZ-ND (substance abuse at psychosis onset), likely attributable to the effects of timing of exposure.

Seasonality of birth in cannabis-induced psychotic disorder

Seasonality of birth in cannabis-induced psychotic disorder

Birth Seasonality of Schizophrenia and Bipolar Disorder? A Review of Inpatient Records

BackgroundNumerous studies on seasonality of birth for mood disorders and schizophrenia have been published but findings are inconsistent 1. We aim to test the hypothesis of lack of seasonal birth differences in hospitalized Bipolar Disorder and Schizophrenia patients. Methods15969 inpatient records in UTHealth Harris County Psychiatric Center between 2012-2014 were enrolled (HSC-MS-14-0274). Patients birth months that were diagnosed as Schizophrenia (n=4178) and Bipolar Disorder (n=5303) according to the DSM IV Criteria were tabulated including admitting diagnosis. Texas Birth statistics between 1903-1997 were obtained as control group (n= 17096471). ResultsThere was no significant difference for winter births between schizophrenia patients and control group (P=0.738) and there was no significant difference for winter births between bipolar patients and control group either (P= 0.862). Mann Kendall Trend Analysis showed no significant trends of birth months for schizophrenia, bipolar and control groups. LimitationsThe study limitations include being a retrospective study, inability to control for environmental factors, and recruiting from a single location. ConclusionsOur large sample showed no association between birth season or months with schizophrenia or bipolar disorder. Severe schizophrenia that requires admission may not be related with birth seasonality.

Season-of-birth phenomenon in health and longevity: epidemiologic evidence and mechanistic considerations.

In many human populations, especially those living in regions with pronounced climatic differences between seasons, the most sensitive (prenatal and neonatal) developmental stages occur in contrasting conditions depending on the season of conception. The difference in prenatal and postnatal environments may be afactor significantly affecting human development and risk for later life chronic diseases. Factors potentially contributing to this kind of developmental programming include nutrition, outdoor temperature, infectious exposures, duration of sunlight, vitamin D synthesis, etc. Month of birth is commonly used as a proxy for exposures which vary seasonally around the perinatal period. Season-of-birth patterns have been identified for many chronic health outcomes. In this review, the research evidence for the seasonality of birth in adult-life disorders is provided and potential mechanisms underlying the phenomenon of early life seasonal programming of chronic disease and longevity are discussed.

출산의 계절성 분석

본 연구는 우리나라 출산의 계절성을 추정하고, 발생 원인에 대해서 논의한다. 인구동향조사를 이용하여 분석한 결과 지난 40여 년 동안 우리나라 출생아수는 연초에서 연말로 갈수록 감소하는 가운데, 9월 전후로 출생아수가 증가하였다가 감소하는 뚜렷한 양상을 보였다. 1월과 2월 출생아수는 연평균 대비 각각 16.1%와 19.6% 더 많은 반면, 6월과 12월 출생아수는 각각 8.4%와 8.9% 더 적었다. 이러한 월별 편차는 2월-3월 격차가 1990년대 이후 감소한 것을 제외하고는 전 기간에 걸쳐 나타났다. 또한 지역, 출생아 성별, 출생순위, 부모의 연령 등 다양한 가구 특성별로 구분하여도 대체로 일관성 있게 관찰되었다. 계절성의 원인에 대한 가설을 시도 단위 자료를 이용하여 검토한 결과, 3월과 6월 사이의 출산빈도 감소는 여름의 고온 다습한 기후에 의해, 6월과 9월 사이의 출산빈도 증가는 연말 혼인빈도의 증가로 설명이 가능한 것으로 나타났다. 연말 대비 연초 출산 선호현상은 기후, 혼인시점, 경제활동으로 설명되지 않아, 앰한나이를 기피하고 취학월령을 높이려는 경향에 기인한 것으로 사료된다.

Lent impact on the seasonality of conceptions during the twentieth century in Spain.

In European past populations, religious canons shaped the seasonal distribution of marriages and births by means of banning weddings and sexual intercourse during important holidays within the religious calendar. In contemporary secularized societies, this seasonal modeling has disappeared. A few pieces of evidence have been gathered to explain how they have disappeared. This paper analyzes the impact of Lent on the seasonality of conceptions during the last century in Spain. Data births of the entire Spanish population born in Spain and alive on the first of January 2003 (more than 39 million) containing the date, size of the municipality (six groups) are used. To analyze this seasonality, we have used time-series techniques. We have built an ad hoc temporal regressor starting from the number of days of Lent that corresponds to each month. We have also used regression models with autoregressive and moving average errors (regARIMA models) to estimate, by maximum likelihood, the set of model parameters. The paper gathers new evidences about the importance of religion on the preproduction of Spanish population until very recently. They show that during the twentieth century, in Spain, there were a significant decrease in conceptions during Lent and a significant rebound after this period. We note that this previous effect disappeared in 1975-1980, when both democracy and the contraception revolution began in Spain. After this period, the seasonality of birth in general disappears.

Impacts of nutrition on reproduction in female red deer: phenotypic flexibility within a photoperiod-mediated seasonal cycle

Red deer (Cervus elaphus) are widely distributed throughout cold northern temperate latitudes, where they have evolved to cope within highly seasonal continental environments. Naturalisation of red deer to the more moderate seasonal (but variable climatic) environment of New Zealand has been spectacularly successful, and they are widely farmed in the country’s pastoral environment for venison and antlers. The species is genetically programmed to exhibit photoperiodic control of voluntary feed intake, growth and reproduction, ensuring that energy demands are aligned with seasonally available resources and offspring are born in summer when climate is favourable for survival. However, despite genetic control of their endogenous seasonal cycles, there appears to be a strong ability for environmental factors such as nutrition to generate large phenotypic variation of seasonal traits. This may have contributed to their successful naturalisation to a wider range of seasonal environments than would be expected within their ancestral range. While precise timing of conception and duration of gestation length are the two fundamental mechanisms by which the strict seasonality of birth is maintained in seasonally breeding mammals, red deer exhibit considerable variation in both these traits. The present paper examines the outcomes of recent studies on farmed red deer on the impacts of lactation on conception date, the influence of nutrition during pregnancy on gestation length, and early life growth effects on the onset of female puberty. These studies have collectively demonstrated that while red deer are assumed to be under fairly rigorous genetic control of seasonality traits, they have a repertoire of phenotypic variation at various points of the reproductive cycle that may potentially allow a degree of adaptation to climatic variation that influences annual feed supply. This may explain the success of red deer in colonising a range of new environments that differ seasonally from their ancestral environment.

No Birth Seasonality of Schizophrenia and Bipolar Disorder: Review of Inpatient Records

Abstract Background Numerous studies on seasonality of birth for mood disorders and schizophrenia have been published but findings are inconsistent 1. We aim to test the hypothesis of lack of seasonal birth differences in hospitalized Bipolar Disorder and Schizophrenia patients. Methods 15969 inpatient records in UTHealth Harris County Psychiatric Center between 2012-2014 were enrolled (HSC-MS-14-0274). Patients birth months that were diagnosed as Schizophrenia (n=4178) and Bipolar Disorder (n=5303) according to the DSM IV Criteria were tabulated including admitting diagnosis. Texas Birth statistics between 1903-1997 were obtained as control group (n= 17096471). Results There was no significant difference for winter births between schizophrenia patients and control group (P=0.738) and there was no significant difference for winter births between bipolar patients and control group either (P= 0.862). Mann Kendall Trend Analysis showed no significant trends of birth months for schizophrenia, bipolar and control groups. Limitations The study limitations include being a retrospective study, inability to control for environmental factors, and recruiting from a single location. Conclusions Our large sample showed no association between birth season or months with schizophrenia or bipolar disorder. Severe schizophrenia that requires admission may not be related with birth seasonality.

Schizophrenia risk factors in exceptional achievers: a re-analysis of a 60-year-old database

Current medical research has focused on diseases and their associated risk factors. As such, these factors are assumed to have a deleterious effect. An alternative hypothesis is that some of these risk factors would also increase the chance for an opposite, positive outcome. To test this hypothesis, we considered exceptional social achievement and schizophrenia as opposite outcomes. Sixty years ago, researchers in France collected data on socio-demographic factors associated with exceptional social achievement. As the number of female subjects in the original database was very limited, we restricted our analyses to men. We tested the odds of achieving prominence in the presence of factors known to be associated with an increased risk of schizophrenia, namely migration, urbanicity, seasonality of birth, birth order, and paternal age. Three of the five factors tested significantly increased the odds for exceptional social achievement (urban birth, being the first-born and father’s age over 35). Our findings suggest that some of the factors that are currently considered as risk factors for schizophrenia could diversifying factors. Widening the focus of research to include all potential effects of factors associated with disease could have important consequences on our understanding of causal mechanisms and for designing public health interventions.

Seasonality of birth affects paediatric coeliac disease.

This study investigated the seasonality of birth in children diagnosed with coeliac disease (CD) at a tertiary University hospital in Southern Israel. This was a population-based retrospective time series analysis study from January 1988 to December 2014. There were 308 903 live births at Soroka University Medical Centre during the study period and 699 were diagnosed with CD. We combined three databases covering births, CD diagnoses and weather indices. The daily proportion of births that resulted in CD for the different four seasons and high seasons were compared to the weather indices on the day of birth using negative binomial regression. Statistically significant associations were found between the season of birth and the rate of CD, with autumn births being associated with a higher risk for the development of CD than births during the summer, with an incidence ratio of 1.22. The association was further increased when the defined summer and autumn high seasons were used, with an incidence ratio of 1.40. No association was found between CD and the mean temperature and global radiation. Coeliac disease was associated with birth during the autumn and the autumn high season posed an even more significant risk factor.

Maternal and neonatal vitamin D status, genotype and childhood celiac disease.

BackgroundLow concentration of 25-hydroxyvitamin D during pregnancy may be associated with offspring autoimmune disorders. Little is known about environmental triggers except gluten for celiac disease, a common immune-mediated disorder where seasonality of birth has been reported as a risk factor. We therefore aimed to test whether low maternal and neonatal 25-hydroxyvitamin D predicted higher risk of childhood celiac disease.Methods and FindingsIn this Norwegian nationwide pregnancy cohort (n = 113,053) and nested case-control study, we analyzed 25-hydroxyvitamin D in maternal blood from mid-pregnancy, postpartum and cord plasma of 416 children who developed celiac disease and 570 randomly selected controls. Mothers and children were genotyped for established celiac disease and vitamin D metabolism variants. We used mixed linear regression models and logistic regression to study associations.There was no significant difference in average 25-hydroxyvitamin D between cases and controls (63.1 and 62.1 nmol/l, respectively, p = 0.28), and no significant linear trend (adjusted odds ratio per 10 nM increase 1.05, 95% CI: 0.93–1.17). Results were similar when analyzing the mid-pregnancy, postpartum or cord plasma separately. Genetic variants for vitamin D deficiency were not associated with celiac disease (odds ratio per risk allele of the child, 1.00; 95% CI, 0.90 to 1.10, odds ratio per risk allele of the mother 0.94; 95% CI 0.85 to 1.04). Vitamin D intake in pregnancy or by the child in early life did not predict later celiac disease. Adjustment for established genetic risk markers for celiac disease gave similar results.ConclusionsWe found no support for the hypothesis that maternal or neonatal vitamin D status is related to the risk of childhood celiac disease.

Seasonality of birth for skin melanoma deserves further investigation

Seasonality of birth for skin melanoma deserves further investigation

Brighter children? The association between seasonality of birth and child IQ in a population-based birth cohort

ObjectiveSeason of birth has repeatedly been found to be a risk indicator for adverse neurodevelopmental outcomes. Several explanations for this finding have been put forward but no conclusion has been...

First Infant Formula Type and Risk of Islet Autoimmunity in The Environmental Determinants of Diabetes in the Young (TEDDY) Study.

Studies on the introduction of infant formulas and its effect on the risk of islet autoimmunity and type 1 diabetes (T1D) have yielded inconsistent results. We investigated whether the introduction of formula based on hydrolyzed cow's milk as the first formula is associated with reduced islet autoimmunity risk in a large prospective cohort. The Environmental Determinants of Diabetes in the Young (TEDDY) study prospectively monitors 8,676 children at increased genetic risk for T1D. Autoantibodies to insulin, GAD65, and IA2 were measured regularly to define islet autoimmunity. Information on formula feeding was collected by questionnaires at 3 months of age. In survival analyses, after adjustment for family history with T1D, HLA genotype, sex, country, delivery mode, breast-feeding ≥3 months, and seasonality of birth, we observed no significant association with islet autoimmunity in infants who received extensively hydrolyzed compared with nonhydrolyzed cow's milk-based formula as the first formula during the first 3 months (adjusted hazard ratio 1.38 [95% CI 0.95; 2.01]), and a significantly increased risk for extensively hydrolyzed formula introduced during the first 7 days (adjusted hazard ratio 1.57 [1.04; 2.38]). Using a partially hydrolyzed or other formula as the first formula, or no formula, was not associated with islet autoimmunity risk. These results add to the existing evidence that islet autoimmunity risk is not reduced, and may be increased, by using hydrolyzed compared with nonhydrolyzed cow's milk-based infant formula as the first formula in infants at increased genetic risk for T1D.