Seasonal Patterns of Birth in Patients with Glioblastoma

Seasonal distribution of birth rates was only recently described in patients with high‐grade gliomas. We analyzed 501 cases from the database of a Regional Cancer Center in Bavaria to assess annual periodicity in the birth dates of glioma patients. Prior to analysis, the number of births per month was normalized [number of births×100,000/total number of births in Germany] to obtain birth rates per month. The approximation of the time series data by a one‐year cosine model found that the glioblastoma birth rate exhibits a statistically significant annual variation, with the peak rate in January. Vitamin intake, infections, and other as‐yet‐unknown factors and exposures during pre‐ and perinatal early life may contribute to the seasonality of birth rate in patients with brain tumors.     

Season of Birth in Schizophrenia in the Mexico City Area: Comparison with General Population

The relationship between seasonal changes and mental disorders has been extensively studied in the northern and southern hemispheres. In both cases, the results show that there is a higher rate of schizophrenic births during the winter months. The present study attempts to prove the existence of this phenomena in Mexico City, an area that does not undergo extreme weather variations throughout the year. A total of 2,288 schizophrenic patients was considered for this study. Their date of birth was compared to that of the general population of the Mexico City area, a total of 4,848,119 individuals. The number of births was evaluated according to the number of days in each month. The distribution of the births of schizophrenics was compared to the reference population by means of a Kolmogorov-Smirnov test and a X 2 contrast. The annual rhythm of births of schizophrenics was determined through an analysis of the Estimated Seasonal Component. There was a slight, non-significant increment in schizophrenic births in December and autumn, as compared with the general population birth rate. Interestingly, it was found that births in the control population decreased significantly in December when compared with all the other months. Results were discussed in relation to the geographical location of Mexico, which lies in a tropical zone, and as a consequence minimal seasonal effects.     

Season of Birth in Schizophrenia in the Mexico City Area: Comparison with General Population

The relationship between seasonal changes and mental disorders has been extensively studied in the northern and southern hemispheres. In both cases, the results show that there is a higher rate of schizophrenic births during the winter months. The present study attempts to prove the existence of this phenomena in Mexico City, an area that does not undergo extreme weather variations throughout the year. A total of 2,288 schizophrenic patients was considered for this study. Their date of birth was compared to that of the general population of the Mexico City area, a total of 4,848,119 individuals. The number of births was evaluated according to the number of days in each month. The distribution of the births of schizophrenics was compared to the reference population by means of a Kolmogorov-Smirnov test and a X 2 contrast. The annual rhythm of births of schizophrenics was determined through an analysis of the Estimated Seasonal Component. There was a slight, non-significant increment in schizophrenic births in December and autumn, as compared with the general population birth rate. Interestingly, it was found that births in the control population decreased significantly in December when compared with all the other months. Results were discussed in relation to the geographical location of Mexico, which lies in a tropical zone, and as a consequence minimal seasonal effects.     

Reproductive parameters of female Japanese macaques: Thirty years data from the arashiyama troops,Japan

Over a 30-year period from 1954 to 1983, 975 live births were recorded for Japanese macaque females at the Iwatayama Monkey Park, Arashiyama, Japan. Excluding unknown birth dates, primiparous mothers gave birth to 185 infants (182 cases with age of mother known) and multiparous mothers gave birth to 723 infants (603 cases with age of mother known). The peak month of birth was May with 52.3% of the total births occurring during the period. Multiparous females who had not given birth the previous year did so earlier than multiparous females who had given birth the previous year and also earlier than primiparous females. Among the females who had given birth the previous year, females whose infant had died gave birth earlier than females who had reared an infant the previous year. The offspring sex ratio (1:0.97) was not significantly different from 1:1, and revealed no consistent association with mother's age. Age-fecundity exhibited a humped curve. The annual birth rate was low at the age of 4 years but increased thereafter, ranging between 46.7% and 69.0%, at between 5 and 19 years of age, but again decreased for females between 20 and 25 years of age. Some old females displayed clear reproductive senescence. The infant mortality within the first year of age was quite low (10.3%) and the neonatal (less than 1 month old) mortality rate accounted for 49.0% of all infant deaths. There was no significant difference between the mortality rates of male and female infants. A female's rank-class had no apparent effect on the annual birth rate, infant mortality, and offspring sex ratio. These long-term data are compared with those from other primate populations.     

ESTIMATING SEA OTTER REPRODUCTIVE RATES

Abstract: Sea otters may give birth in any month of the year, so obtaining reproductive rates by observation is difficult. Reproductive rates may be estimated directly (births per otter-year observed) or by determining the time interval between births. Both methods give the same result for long sequences of observations, but field data are limited to shorter periods. Monte Carlo simulations were conducted to compare the two approaches, and showed that the interval method overestimates true reproductive rates.     

Are all born equal? Incidence of febrile convulsions by seasons of birth.

To test whether the seasons of birth had an effect on subsequent experience of illness, details were obtained of all Sheffield children born between 1973 and 1977 who were admitted to hospital before their second birthday with a first febrile convulsion. Analysis by date of birth in consecutive 28-day cohorts showed that the incidence of febrile convulsions ranged from 2.5 per thousand live births to 30.2 per thousand in different "month" cohorts. Statistically significant variations were noted in the incidence rates in relation to season and year of birth. The implication is that even large scale epidemiological studies which have been confined to children born in a particular week or month may not be representative of the whole child population.     

Birth Month and Risk of Glioma in Adults: A Registry‐Based Study in Bavaria

The aim of the present study was to evaluate the possible seasonality of birth in adult patients suffering from glioma. For this purpose, data from the database of the population‐based cancer registry of Bavaria (Germany) were retrieved. For the period 2002–2005, we identified a total of 2174 patients born between 1931 and 1986 diagnosed with malignant glioma. Statistical analyses failed to document a significant annual periodicity of glioma risk in either men or women with respect to birth month in the observed cohort. Thus, we found no association between month of birth and the risk of glioma. In contrast, an analysis of the official birth rate data of Bavaria revealed marked annual variation in birth rates up until 1965, which decreased markedly in prominence in the years thereafter. Our findings confirm the results of a recent similar study conducted in The Netherlands. Therefore, we support the hypothesis of possible etiological factors of glioma acting in adulthood rather than in the perinatal period.     

A ten-year summary of reproductive parameters for ring-tailed lemurs at berenty, madagascar

From 1989 to 1998, 204 live births were recorded for ring-tailed lemurs (Lemur catta) at Berenty, Madagascar. Excluding unknown birth dates, the peak month of birth was September, with 82.0% (146/178) occurring during this period. The offspring sex ratio (1∶1.19) was not significantly different from 1∶1, and there was no association with the mother's age. The first births occurred at the ages of 2 to 4 yr. The annual birth rate was very low at the age of 2 yr (11.1%), but increased thereafter: to 50.0% at the age of 3 yr, and to 75–85% at the age of 4 or more years. Multiple births were very rare, since only three sets of twins and one set of triplets were recorded. As for the interbirth interval, a one-year interval was the most common (92.2%). Infant mortality within the first year was 37.7% (77/204). Neonatal mortality within the first month accounted for 31.2% of all infant dealths.     

Seasonal variation of livebirths, stillbirths, extramarital births and twin maternities in Switzerland.

A study was made of the seasonal variation in all births, and births according to marital status, multiplicity and birth status (live and still) in Switzerland recorded between 1876 and 1990. To obtain seasonal variation in as pure as possible form, our analyses are based on rates. When comparing the seasonality in data sets showing markedly different levels, standardised indices were used. Assuming the length of pregnancies with twins to be about one month shorter than for pregnancies with singletons, lagged twinning rates were calculated but, in comparison with actual twinning rates, the general seasonal variation remained. Therefore, this study was based on actual twinning rates. A monotonic increase in the amplitude of the seasonal variation in general births was noted for the period 1876-1930, with strong seasonal variation holding for 1921-1980. After that, a marked decline in the amplitude can be observed. Seasonality of both all births and twin maternities showed very similar pattern for the periods 1876-1930 and 1969-1990, with maxima in the spring (March-May) and troughs in late autumn (October-December). Twin maternities showed a strong seasonality for the period 1876-1930, being about 20% higher in March than in October. The twinning rate in the period 1876-1930 was about 2.6 per thousand units higher than in the period 1969-90. For twin maternities there was also a stronger seasonal variation during the earlier period than during the later one. The pattern of the seasonal variation for extramarital births, showing a maximum in February (conceptions in May-June) and a minimum in August (conceptions in November-December) with a difference of no less than 24% was more marked than for the marital births. It seems likely that this seasonality of extra-marital maternities was due mainly to seasonal variation of coital rates and multiple ovulation in the early summer months coinciding with optima of light, temperature and food supply. A strong reduction in the rate of stillbirths (gestational age more than 29 weeks) was observed during the twentieth century. The stillbirth rate declined from about 40 per 1000 in the 1870s to fewer than 5 per 1000 in the 1980s. Irrespective of this strong decline in the stillbirth rate, the same seasonal rhythm was noticed throughout the period with high stillbirth rates among births around March and low rates during the summer and autumn.     

Incidence rates for cleft lip and palate in British Columbia 1952-71 for North American Indian, Japanese, Chinese and total populations: secular trends over twenty years

The incidence of cleft lip and/or cleft palate was examined for the 1952-71 period for the Province of British Columbia. Although there were some fluctuations, some of which were significant, there was no general trend which indicated that the rates were either increasing or decreasing. These rates are important for a background calculation when investigating new invironment teratogens. The total rate of 1.97 per 1,000 live birth is comparable with other Caucasian populations where there is good ascertainment and adequate follow-up period. This study also confirmed the previously reported high rate for North American Indians in British Columbia (3.74 per 1,000 live births) and established rates for the Japanese (3.36 per 1,000 live births) and Chinese (1.76 per 1,000 live births) of British Columbia. Since these three sub-populations are relatively small in relation to the total population, they do not influence the overall total rate to any great extent.     

Variation of sex ratio and ABO blood group composition by month of birth of blood donors in Tokyo

Sex ratio of 17,273 blood donors born during the period between 1925 and 1935 was examined according to their month of birth and ABO blood groups in comparison with 5,810 healthy non-blood donors born in the 1900s to 1930s. The sex ratio of the blood donors and the non-blood donors varied similarly according to their month of birth with a prominent peak in summer births and a trough in winter births. This birth season with a high sex ratio was different from that of the general births during the period between 1921 and 1935, in which a maximum sex ratio was found in November. A possible explanation for the difference is the different rate of male and female infant deaths according to birth month. Variation of the sex ratio according to season of birth was not similar among the four ABO blood groups. Sex ratio of the donors with blood group B showed no elevation among the summer births. Non-blood donors with blood group B, on the contrary, showed a higher sex ratio than the others in the summer births. This difference can not be explained by infant or juvenile deaths. A possibility is that a tendency to become a blood donor is modified by the season of one's birth differently according to gender and ABO blood groups.     

Elective frozen-thawed embryo transfer (FET) in women at risk for ovarian hyperstimulation syndrome

Elective cryopreservation of cultured embryos has become a treatment option for women at risk for ovarian hyperstimulation syndrome (OHSS). The aim of our study was to investigate the outcome of elective cryopreservation and consecutive frozen-thawed embryo transfer (FET) in a large IVF clinic in Austria. A total of 6104 controlled ovarian hyperstimulation cycles (COH) were performed on 2998 patients including 200 patients (6.7%) who were undergoing elective cryopreservation and FET due to high risk of OHSS. We estimated the cumulative live birth rate using the Kaplan-Meier method and evaluated independent predictors for successful live births with a Cox model. A total of 270 frozen-thawed embryo transfers were performed on 200 patients with up to 4 transfers per patient. The first embryo transfer showed a live birth rate of 42.0%, the second transfer showed a cumulative rate of 58.5%. After a total of 4 FETs from the same COH cycle, a cumulative live birth rate of 61.0% per COH cycle could be achieved. Four cases of OHSS occurred amongst these patients (2.0%), all of them of moderate severity. Multivariate analysis identified maternal age, the use of assisted hatching and the number of embryos transferred at the blastocyst stage as independent predictors for cumulative live birth. Our study clearly suggests that elective FET is safe and shows excellent cumulative live birth rates. This concept can, therefore, be used to avoid the severe adverse events caused by COH and the inefficient use of cultured embryos.     

Influence of month and climatic factors on the period of birth,litter size,birth weight and preweaning mortality of sheep in Ghana

Relationships between month and clinatic factors-rainfall, ambient temperature, relative humidity (RH) and temperature-humidity index (THI)-with time of parturition, litter size, birth weight and preweaning mortality were studied in Djallonke and Dja lonke x Sahelian sheep. Births (4142) occurred all year round although there were significant differences in the number of births per month. Maximum litter size did not coincide with the maximum births. Peak conceptions occurred in the early parts of the major rainy season. There were also significant differences in birth weights and mortalities (%) per month. Maximum and minimum values (of birth weighs and mortalities) occurred in the latter part of the rainy seasons and dry periods respectively. There were significant positive correlations between litter size and cumulative rainfall in the 4th–6th months periods prior to lambing. Birth weights of both males and females were positively and significantly associated with minimum temperature and cumulative rain-fall in the 2- and 3-months period prior to lambing respectively. There were significant positive correlations between mortality and minimum and maximum RH and cumulative rainfall in the 3 months after lambing.     

Increasing pre-term and low-birth-weight rates over time and their impact on infant mortality in south-east Brazil

This study investigates the possible effects of pre-term births and low birth weight on infant mortality rates (IMRs) over a 15-year period in Ribeir?o Preto, Brazil, based on surveys carried out in 1978/79 and 1994. The 1978/79 survey included 6750 births over a 12-month period and the 1994 survey 2846 births over a 4-month period. Infant deaths were retrieved monthly from the city register. Infant mortality rate decreased from 36.6 to 16.9 deaths per 1000 over 15 years. The decrease in IMR was larger in the 2500-2999 g group than in any other group. The observed falls in IMR were attributable to decreases in birth-weight-specific mortality rates. Likewise, there was a general decrease in IMR in mild, moderate and severe pre-term births. The incidence rate ratio of infant mortality between surveys was 0.46 (95% CI 0.34-0.63); it increased to 0.57 (95% CI 0.35-0.75) when adjusted for birth weight and other factors in the model and rose to 0.69 (95% CI 0.49-0.97) when adjusted for length of gestation and other variables. The increase in pre-term births and low birth weight may have had, at most, a marginal effect on the IMR. Progress in the care of newborns may have decreased the mortality risk, but even mild pre-term birth still has an impact on infant mortality. There is room for further improvement in IMR by tackling the high rates of pre-term birth.     

Monitoring the trend of the transmission rate of vertically acquired HIV infection: a simple method applied to Italian data.

The objective of this study was to develop and validate a method for estimating and monitoring over time the transmission rate of vertically acquired HIV infection at the population level. We estimated the annual number of children born to HIV-infected women in Italy in 1991-1994 by multiplying the seroprevalence rates, provided by Anonymous Unlinked HIV Serosurveys among Italian Newborns, by the annual number of births, provided by the Italian National Institute of Statistics. The number of HIV-infected children was estimated by applying a simplified back-calculation method to the incident cases of vertically acquired AIDS reported to the AIDS surveillance registry, using seven different estimates of the distribution of the incubation period identified through a literature search. The annual vertical transmission rates were estimated by dividing the estimated number of children with vertically acquired HIV infection by the estimated number of births to an HIV-infected mother. Depending on the chosen distribution of the incubation period, the estimated transmission rate for the four-year period ranges from 0.10 to 0.30. Five of the seven incubation distributions provided a rate falling within the very narrow interval 0.18-0.20. The method provided estimates of vertical transmission rates consistent with those of longitudinal studies performed in European countries. The method presented here could be useful for monitoring the impact of interventions aimed at reducing HIV vertical transmission rate.     

Impact of Birth Seasonality on Dynamics of Acute Immunizing Infections in Sub-Saharan Africa

We analyze the impact of birth seasonality (seasonal oscillations in the birth rate) on the dynamics of acute, immunizing childhood infectious diseases. Previous research has explored the effect of human birth seasonality on infectious disease dynamics using parameters appropriate for the developed world. We build on this work by including in our analysis an extended range of baseline birth rates and amplitudes, which correspond to developing world settings. Additionally, our analysis accounts for seasonal forcing both in births and contact rates. We focus in particular on the dynamics of measles. In the absence of seasonal transmission rates or stochastic forcing, for typical measles epidemiological parameters, birth seasonality induces either annual or biennial epidemics. Changes in the magnitude of the birth fluctuations (birth amplitude) can induce significant changes in the size of the epidemic peaks, but have little impact on timing of disease epidemics within the year. In contrast, changes to the birth seasonality phase (location of the peak in birth amplitude within the year) significantly influence the timing of the epidemics. In the presence of seasonality in contact rates, at relatively low birth rates (20 per 1000), birth amplitude has little impact on the dynamics but does have an impact on the magnitude and timing of the epidemics. However, as the mean birth rate increases, both birth amplitude and phase play an important role in driving the dynamics of the epidemic. There are stronger effects at higher birth rates.     

Twinning rates in a rural area of Bangladesh

In this study we investigate the incidence of twin births over a period of 16 years in a rural area of Bangladesh using data from the Demographic Surveillance System of the International Centre for Diarrhoeal Disease Research. Over the study period twinning rates fluctuated between 7.8 and 11.2 per 1000 live births. The twinning rate was strongly correlated with maternal age; the rate for mothers over 35 years of age was about 3 times higher than for mothers younger than 20 years. The variation in twinning rate with maternal age is due to the variation in dizygotic twinning; the rate of monozygotic twinning is almost constant for all ages. Twinning rates were higher in the treatment area than in the comparison area after controlling for maternal age and parity. The rates were lower for monozygotic twinning and higher for dizygotic twinning in the treatment area than in the comparison area. Seasonality was observed for both twins and singletons, but the peak for twinning precedes that for singleton births by more than a month.     

A multiple pregnancy register in the north of England.

A regional population-based Multiple Pregnancy Register was established in 1998, with the aim of collecting detailed information on multiple pregnancies to enable research into mortality and morbidity in multiples. Multiple pregnancies are notified to the Register as soon as they are detected, irrespective of whether they resulted in a spontaneous abortion, termination of pregnancy or registered birth. Nine hundred and twenty-six twin pregnancies were recorded during 1998-99, giving a twinning rate of 14.8 per 1000 maternities (rate at birth 13.0 per 1000 maternities). Sixty one per cent of twin pregnancies were detected before 13 weeks of gestation. Chorionicity was determined in 82.6% of 849 twin maternities with at least one stillbirth or livebirth. The fetal loss rate before 24 weeks of gestation was 10.5% (194/1852). The perinatal and infant mortality rates were 40.6 per 1000 births and 32.6 per 1000 livebirths respectively. A prospective Multiple Pregnancy Register not only allows monitoring of trends in multiple birth rates and mortality, but also etiological research and long-term follow-up studies.     

Perinatal mortality and adverse pregnancy outcomes in a low-income rural population of women who smoke

We describe adverse pregnancy outcomes, including congenital anomalies, fetal, neonatal, and infant mortality among a Missouri population of low-income, rural mothers who participated in two randomized smoking cessation trials. In the Baby BEEP (BB) trial, 695 rural women were recruited from 21 WIC clinics with 650 women's pregnancy outcomes known (93.5% retention rate). Following the BB trial, 298 women who had a live infant after November 2004 were recruited again into and completed the Baby Beep for Kids (BBK) trial. Simple statistics describing the population and perinatal and postneonatal mortality rates were calculated. Of the adverse pregnancy outcomes (n = 79), 29% were spontaneous abortions of less than 20 weeks' gestation, 23% were premature births, and 49% were identified birth defects. The perinatal mortality rate was 15.9 per 1000 births (BB study) compared with 8.6 per 1000 births (state of Missouri) and 8.5 per 1000 births (United States). The postneonatal infant mortality rate was 13.4 per 1000 live births (BBK) compared with 2.1 per 1000 live births (United States). The health disparity in this population of impoverished, rural, pregnant women who smoke, particularly in regard to perinatal and infant deaths, warrants attention.     

Descriptive epidemiology of anophthalmia and microphthalmia, Hawaii, 1986-2001

BACKGROUND: Population-based epidemiologic data on anophthalmia and microphthalmia in the United States are limited and have come mainly from only a few states. The intent of this study was to report on the epidemiology of these eye defects. METHODS: Cases were derived from a population-based birth defects registry in Hawaii and comprised all infants and fetuses with anophthalmia and microphthalmia who were delivered during 1986-2001. Anophthalmia and microphthalmia rates per 10,000 births were determined for selected factors, and comparisons were made by calculating the rate ratios and 95% confidence intervals (CIs). RESULTS: Ninety-six cases of anophthalmia and microphthalmia were identified, with a rate of 3.21 per 10,000 live births. The eye defects were isolated in 5 cases (5.2%), and 24 cases (25.0%) had confirmed chromosomal abnormalities. The risk of anophthalmia and microphthalmia varied over time and was significantly higher for live-born infants with low birth weights and gestational ages. The anophthalmia and microphthalmia rates also varied by maternal race/ethnicity, sex, and plurality, although these differences were not statistically significant. CONCLUSIONS: Anophthalmia and microphthalmia frequently occurred with other birth defects, and the rate was consistent with that found in the literature. The risk of defects differed significantly with time period, birth weight, and gestational age. The impact of many factors on anophthalmia and microphthalmia in Hawaii was frequently consistent with that reported elsewhere.