Menarche, pregnancy, birth spacing and menopause among the Agta women foragers of Cagayan province, Luzon, the Philippines

The reproductive histories of 74 post-menarcheal Agta Negrito women, tropical foragers of Cagayan province, north-eastern Luzon, the Philippines are described and analysed in comparison with data collected by Howell on Dobe !Kung hunter-gatherers. Among the Agta, mean age at menarche is 17, mean age at first live birth is 20.14 years, mean completed parity is 6.53 and mean age at menopause is 44. Average height is 141.24 cm and average weight 36.72 kg. No time trends were detected in age at menarche and age at first live birth among the Agta. Average spacing between live births where an infant survives until the birth of the next sibling was 2.85 years. Compared to the Dobe !Kung, Agta women have later menarche, but shorter birth spacing and a longer active childbearing span.     

Physiological maturation,reproductive patterns,and female fecundability in a traditional Moroccan population (Amizmiz,Marrakech)

The interaction between age at menarche, adolescent motherhood, and subfecundity were evaluated in 496 Moroccan women 25–54 years of age from the province of Marrakech. Since this population is characterized by later sexual maturation and early marriage, significantly increased subfecundity, measured by the waiting time to first live birth and the incidence of fetal loss, was expected. Menstrual age was defined as the difference between age at marriage and age at menarche. Social access to reproduction was conditioned by age at menarche: early maturers married at a younger age, while late maturers had a significantly shorter menstrual age despite the fact that married at a significantly older age. Although there was a tendency for late maturers to have longer waiting times and more fetal loss, there were no significant differences for either variable according to menarcheal age. Women with a shorter menstrual age became pregnant within the first year after marriage significantly less frequently than women with a greater menstrual age, but did not experience a greater occurrence of fetal loss during their reproductive life. The results indirectly support the hypothesis that the regularity of ovarian function is similar among populations independent of the timing of menarche. © 1993 Wiley-Liss, Inc.     

Age at menarche in deaf girls

Using the status quo and retrospective methods, age at menarche was estimated for a sample of 212 deaf girls 7 through 20 years of age. Median age at menarche via probit analysis was 11·91 ± 0·25 years, while the mean based on recalled age in older girls (≥ 15·5 years) was 12·56 ± 0·16 years. These two estimates thus differ by approximately 0·6 years. The probit estimate of median age at menarche in deaf girls is similar to mean ages reported for blind girls. However, the retrospective age is later. Thus, the present data are inconclusive as to whether the sensory deprivation imposed by deafness has an accelerating effect on menarche similar to that hypothesized for light deprivation in blind girls.     

Early childhood determinants of age at menarche in rural guatemala

The influence of early childhood determinants on age at menarche was investigated in a sample of Guatemalan women who participated as children in a nutrition intervention study conducted from 1969 to 1977. Age at menarche was retrospectively estimated in 1991 and 1992. Mean age at menarche was 13.7 (±1.3) years. Data on linear growth, diarrhea and respiratory illnesses, and energy intake from supplementation as well as home sources were available between birth and 7 years of age. Socioeconomic status (SES) data were collected in 1975. Four hundred and ninety-seven women who had reached menarche by 1992 were grouped into three categories of stunting based on their height-for-age z-scores (none, >−2.0; moderate, −2.0 SD to −3.0 SD; severe, <−3.0 SD relative to National Center for Health Statistics reference data) at 3 years of age. About 78% of the sample was moderately or severely stunted at 3 years of age. The group that was severely stunted in childhood reached menarche at 14.1 ± 1.4 years, significantly later than those who were moderately stunted (13.7 ± 1.2 years) or not stunted (13.5 ± 1.3 years). Using multiple linear regression methods, stunting was a significant predictor of age at menarche. Average energy intake (kcal/d) from home diet was associated with earlier menarche independent of preschool growth status. Percent time ill with diarrhea was positively associated with age at menarche. When the effects of diet, supplement, percent time ill with diarrhea and respiratory illnesses, and SES were taken into account, the independent influence of stunting on age at menarche persisted and remained significant. © 1996 Wiley-Liss, Inc.     

Menarcheal age for Norwegian women born 1830–1960

Data from birth records from the maternity hospitals in the three main cities in Norway have been used to study the trend in menarcheal age for women born from about 1830 to about 1960. The investigation is based on a sample of 200–300 records around every 10th year from each of the three clinics in partly overlapping time periods relating to a total of 9152 women. The recollected age at menarche fell from just above 16 years for women born around 1830 to just above 13 years for those born around 1960, the decrease being not totally linear. These results correspond closely with a previously published investigation from Oslo from about the same period of time (Brudevoll, Liestøl and Walløe, 1979), but our results, which cover more of Norway, show a more linearily shaped curve than the results covering only Oslo. We have also analysed the relationships of several independent variables to menarcheal age, using multivariate linear regression methods. Besides the woman's year of birth, which was the most important variable throughout the whole period of time, various geographical variables were found to be of moderate importance. Being born in the countryside and in towns other than Oslo and Bergen led to a slightly higher age at menarche. No significant difference between Oslo, Bergen and Trondheim was detected except for the period up to about 1880 where the Bergen women had about 2·6 months earlier menarche than the Oslo women. Married women amongst the sample had experienced menarche a little earlier than the unmarried, and among married women there was an association between occupation and menarcheal age, women from the lowest social classes having the latest ages at menarche. The importance of these socially related parameters declined with time, and for women born after 1945 the difference seemed to have disappeared. The age at menarche was found to be positively related to a woman's age at first birth; the further back in time the stronger the relation. In addition, delayed age at menarche was also found to be associated with irregularities in the menstrual cycles in later life.     

Weight status of adult !Kung San and Kavango people from northern Namibia

An anthropometric assessment was conducted at 238 !Kung San hunter-gatherers aged between 18 and 65 years (mean = 30.8 years), 156 Kavango horticultural pastoralists aged between 18 and 61 years (mean = 29.2 years) and for 87 urbanized kavango people aged between 18 and 61 years (mean = 29.3 years) living as wage earning employees in northern Namibia. Weight status was estimated by using body mass index categories according to the recommendations of the WHO. As is typical for human populations, men were taller and heavier than women within the same ethnic groups. An interethnic comparison showed that both !Kung San women and men were lighter than Kavango women and men. The mean BMI of !Kung San women was 19.1 and of !Kung San men 19.4 kg/m². Kavango people exhibited higher average BMI values, 19.4 for women, 20.3 kg/m² for men. With the exception of the male urban Kavango people a high percentage (more than 30%) of the subjects were thin and underweight, as shown by a BMI of < 18.5 kg/m². This was especially true of the !Kung San of both sexes and the rural Kavango men. Nearly 25% of !Kung San women met the criterion of weight depletion (BMI < 17.0). The cultural transition from nomadic hunter gatherer subsistence to a more sedentary life style over the last 20 years can be interpreted as an environmental stress which affected male as well as female nutritional status. The hard economic situation of the rural Kavango people may also be a stress factor which negatively influenced their nutritional status, especially of the men. The significantly better nutritional status of the urban Kavango men may be the result of the opportunities for work as wage carners or as soldiers.     

Menarcheal age in Oslo during the last 140 years

Data from maternity clinics have been used to study the trend in menarcheal age among girls born in Oslo after 1840. The investigation was based on recordings from approximately 50 women from each year. The women were divided into social categories according to their own or their husband's occupation. The results show a trend toward earlier maturation within the working class, which is characterized by two periods of rapid fall in menarcheal age. The first period covers women born between 1860 and 1880, and shows a fall in menarcheal age from about 15·6 to about 14·6 years. During the second period of rapid fall, which covers women born between 1905 and 1940, the menarcheal age was further reduced from about 14·6 to 13·3 years. The age at menarche has been stable at about 13·3 years for women born after 1940.

These results contrast with those of some earlier studies of the menarcheal age in Norway. However, it is shown that the discrepancies between these investigations and our own disappear when the same computational methods and the same interpretation of the age recordings are used.     

Secular trend in age at menarche for women born between 1920 and 1979 in Rio de Janeiro, Brazil

PRIMARY OBJECTIVE: This article presents data on the secular trend in age at menarche for 1955 women from 16 to 76 years of age born between 1920 and 1979 and studied under the Nutrition and Health Survey conducted in the municipality of Rio de Janeiro, Brazil, in 1996. METHODS AND PROCEDURES: Age at menarche was defined by the retrospective method. Women were grouped according to decade of birth, and the trend was estimated using simple linear regression between age at menarche and year of birth for the following specific periods: 1920-1940, 1920-1960, 1960-1979 and 1920-1979. MAIN OUTCOMES AND RESULTS: Mean age at menarche decreased from 13.07 to 12.40 years when comparing the group of women born in the 1920s with the 1970s birth cohort, corresponding to a mean rate of -0.0123 years per year (p < 0.001). The downward trend was -0.0120 years per year (p > 0.05) for the 1920s, 30s and 40s, -0.0093 years per year (p < 0.05) for the period from 1920 to 1960, and -0.0224 years per year (p < 0.01) for the 1960s/70s. CONCLUSIONS: The results suggest a secular trend in age at menarche. The literature points to such environmental variables as improved living conditions and expanded access to health services. Within this context, age at menarche could be used as a marker for social development.     

Biological correlates of modernization in a Guatemalan highland municipio

The demographic correlates of modernization were studied in a municipio of the Guatemalan highlands using, as indicators of modernization, the introduction of chemical fertilizers and of a religious revitalization movement, Accion Catolica. Records, taken from interviews, of 340 women divided into declines (decennial groups) within ten-year birth cohorts extending from before 1925 to 1954, were checked for representativeness against the birth registries for the entire municipio for the years 1965–69.

A steady decrease in the age of marriage of successive cohorts, based on probits, from 17·4 to 14·2 years, occurred, and the age at first birth declined from 20·9 to 15·9 years. There has also been a steady increase in the mean number of livebirths so that, e.g., the 10–19 year decline of the youngest cohort has more than doubled the number of live births of the same decline among the oldest cohort. Pre-school mortality of children has fallen drastically which, combined with increased fertility, has resulted in rapid population growth. These changes are seen as correlates of and quite possibly biological responses to those cultural changes which accompany modernization.     

Secular trend in the age at menarche in Haiti

Trends in age at menarche of 10,563 pregnant Haitian women enrolled in a longitudinal study of maternal mortality are examined. Mean recalled age at menarche for adult women in the sample was 15.37 years. However, there was a clear decline in mean menarcheal ages from the oldest to the youngest women, with a mean rate of decline for adult women of 0.36 years per decade. Mean menarcheal age was higher in each age group of rural women than for women in the metropolitan Port-au-Prince area; the rate of decline for adult rural women (0.37 years per decade) was nonsignificantly higher than that for adult metropolitan women (0.30 years per decade). The data suggest a secular decline in age at menarche in Haiti, as well as a continuing disparity between metropolitan and rural women. A declining age at menarche has important implications for fertility and reproductive health in Haiti, and may reflect a gradual improvement in health and nutritional status. © 1995 Wiley-Liss, Inc.     

Age at menarche in Ceylon

The age at menarche in girls in schools in Colombo city, Ceylon, in 1968, was estimated by probit analysis as 13·72 ± 0·12 years. This figure is higher than that of 12·84 years obtained in 1950 by a similar analysis. The exact date at menarche was forgotten by 15·5% of the sample but all alleged they remembered the year of age at which it was reached. However, cohort analysis gave a higher mean value than probit analysis, indicating that some girls recollected wrongly, even though special ceremonies attend the event in Ceylon.     

Social background and age at menarche in Portuguese university students: A note on the secular changes in Portugal

Menarcheal age of a sample of Portuguese university students (n = 3,366), born between 1972 and 1983, age 18–23 years, was analyzed. The influence of parents' educational level and occupation, family size, birth order, and degree of urbanization of girl's locality of residence during childhood and adolescence were analyzed as well as secular trend in the Portuguese population. Mean age at menarche for girls born in 1983 was 12.32 years. Parents' educational level and occupation did not show any significant influence on mean age at menarche. Place of residence during childhood years and adolescence showed a significant effect on mean age at menarche, with girls from rural places with a later age at menarche than those who spent their childhood or adolescence in urban areas (P ≤ 0.01 and P ≤ 0.05 for childhood and adolescence, respectively). Family size and birth order showed the highest effect. Girls born in small families, with one child, matured earlier (12.32 years) than those born in large families with four or more children (12.67 years), (P ≤ 0.01). Also, girls that were first‐born had an earlier menarche (12.41 years) than those who were third or later (12.58 years, P ≤ 0.01). Regression analysis selected family size and place of residence in childhood as the most important determinants of mean age at menarche in our university students. In this sample, from 1972 to 1983, mean age at menarche remained stable. When we considered published data from all the Portuguese population we found a decrease in mean age at menarche from 15 years for girls born in 1880 to 12.44 for those born in the 1980s. This decrease was the result of great improvements in the social and economic living conditions that occurred in Portugal especially after the 1970s concerning nutrition and health care, among many other environmental factors. Am. J. Hum. Biol. 15:415–427, 2003. ©2003 Wiley‐Liss, Inc.     

Changes of recollected menarcheal age and month among women in Tokyo over a period of 90 years

Data on the recollected age at menarche of 47,881 women born between 1881 and 1970 were examined. The mean menarcheal age had changed from 15.1 years in those born up to 1900 to 12.5 years in those born during the 1960s. The age at menarche differed according to the month of birth, and the pattern of average age distribution by month of birth was not the same when the year of birth was different. Among women born before 1955 the menarcheal age was earlier in those born in the summer. However, among women born after 1955, menarche occurred later when they were born in the summer. The monthly distribution of menarche had also changed during this 90-year period. Two peaks in April and August were prominent among those born up to 1960. A third peak in January became also apparent in those born after 1960.     

Prevalence of menstrual pain in relation to the reproductive life history of women from the Mayan rural community

BACKGROUND: The prevalence of menstrual pain in Western societies is relatively high and has been shown to be related to many factors (e.g. age, menarche age, parity, menstrual cycle regularity, cigarette smoking, dietary habits). However, less data are available for traditional societies, within which there are, presumably, not as many potentially disturbing factors that could influence menstrual symptoms as in Western societies. AIM: The study seeks to determine the prevalence of dysmenorrhoea, and the factors related to menstrual pains in women with natural fertility (i.e. without hormonal forms of contraception). SUBJECTS AND METHODS: 177 non-smoking women between 18 and 45 years of age living in one Mayan village (Yaxcaba, Yucatan, Mexico) were the subjects of this study. The method of logistic regression was used with the dichotomous dependent variable being the presence or absence of menstrual pain together with such independent variables as age, age at menarche, number of pregnancies, age when giving birth to the first child, the weight at interview and BMI. RESULTS: The general prevalence of the menstrual pains was 28%. There was only one variable influencing dysmenorrhoea, namely the age at which women give birth to their first children. Those mothers who gave birth to their first child at an earlier age (at mean age of 19.4 vs 21.1 years) had a lower prevalence of dysmenorrhoea. CONCLUSION: In the studied traditional society the main factor related to menstrual pain was the age at which woman first gave birth. It is hypothesized that an earlier start to reproductive life in some way decreases the sensitivity of the uterus to prostaglandins.     

CYP Gene Polymorphisms and Early Menarche

Early age at menarche is a risk factor for breast cancer. A previous study reported a significant positive association between the CYP3A4*1B variant allele and early puberty. We investigated whether polymorphisms of the CYP3A4, CYP17, CYP1B1, and CYP1A2 genes predict the age at onset of menarche. Five hundred eighty-three nulliparous women between ages 17 and 35, of various ethnic backgrounds, completed a questionnaire that included information about menstrual history. Samples of DNA were provided and used to genotype these women for polymorphic variants in the four genes. There was no significant difference in mean age at menarche between women who carried two variant CYP17 A2 alleles (12.5 years) and women who carried one or no variant allele (12.5 years) (P = 0.8, adjusted for ethnic group and year of birth). Similar results were found for the CYP1B1*3 variant allele and for the CYP1A2*1F variant allele. Women who carried two variant CYP3A4*1B alleles had an earlier mean age at menarche (12.0 years) than women who carried one or no variant allele (12.6 years) (P = 0.02). However, after adjusting for ethnic group and year of birth, no significant differences in mean age at menarche were found. The polymorphic variants of the CYP3A4, CYP17, CYP1B1, and CYP1A2 genes are unlikely to influence age of menarche.     

One year follow-up study of stature,weight, emergence of dentition,and sexual maturation of well-nourished indian girls from birth to 20 years

Stature, weight, and emergence of deciduous and permanent teeth of 1,330 well-nourished girls from birth to 20 years belonging to well-off families residing in Delhi are reported. All subjects were measured on two occasions 1 year apart. In addition, each subject was examined for gingival emergence of deciduous or permanent teeth on both occasions. Data on age at menarche were also collected. Single-year velocities of stature and weight are highest during the first year. The peak of adolescent spurts in stature and weight velocities are observed at 11.0 and 12.0 years, respectively. The first deciduous tooth to emerge is the mandibular I₁, of girls at 7.6 months. The sequence of emergence based on ascending median ages is I1, I2, M1, C, and M2 for both maxillary as well as mandibular deciduous teeth. The permanent dentition starts with the emergence of mandibular M₁ at 5.75 years. The sequence of emergence of permanent teeth is M¹, I¹, I², PM¹, C, PM², and M² in the maxilla, and M₁, I₁, I2, C, PM₁, PM₂, and M₂ in the mandible. Annual increase in number of permanent teeth erupted shows a spurt between 9 and 10 years of age. Median age at menarche is 12.37 ± 0.03 with a standard deviation of 0.8 years; it is about one and one-half years later than the estimated age at peak height velocity. Single-year velocities of stature and weight decline after the onset of menarche. An association of emergence of deciduous teeth with birth weight is observed. Newborns with higher birth weight tend to have more teeth emerged at one year of age compared to those having lower birth weight. In all age groups, girls who had experienced menarche are taller and heavier and have more erupted permanent teeth compared to those who have not yet attained menarche. Girls with earlier menarche apparently have short adult stature compared to those with later menarche. © 1994 Wiley-Liss, Inc.     

CYP gene polymorphisms and early menarche.

Early age at menarche is a risk factor for breast cancer. A previous study reported a significant positive association between the CYP3A4*1B variant allele and early puberty. We investigated whether polymorphisms of the CYP3A4, CYP17, CYP1B1, and CYP1A2 genes predict the age at onset of menarche. Five hundred eighty-three nulliparous women between ages 17 and 35, of various ethnic backgrounds, completed a questionnaire that included information about menstrual history. Samples of DNA were provided and used to genotype these women for polymorphic variants in the four genes. There was no significant difference in mean age at menarche between women who carried two variant CYP17 A2 alleles (12.5 years) and women who carried one or no variant allele (12.5 years) (P = 0.8, adjusted for ethnic group and year of birth). Similar results were found for the CYP1B1*3 variant allele and for the CYP1A2*1F variant allele. Women who carried two variant CYP3A4*1B alleles had an earlier mean age at menarche (12.0 years) than women who carried one or no variant allele (12.6 years) (P = 0.02). However, after adjusting for ethnic group and year of birth, no significant differences in mean age at menarche were found. The polymorphic variants of the CYP3A4, CYP17, CYP1B1, and CYP1A2 genes are unlikely to influence age of menarche.     

Age of menarche in Oaxaca,Mexico, schoolgirls,with comparative data for other areas of Mexico

Status quo menarcheal information was collected for a mixed urban colonia and rural sample of 315 girls in the Valley of Oaxaca, Mexico. Comparative status quo data for girls from four major urban centres in Mexico and for a rural sample were also analysed. Median age at menarche (estimated by probit analysis) for Oaxaca girls was 14·27±0·20 years, about 0·5 year later than that for the rural sample from Tampico-Altamira, Tamaulipas (13·79±0·20 years), and approximately 1·5 years later than that for girls from the four urban centres in Mexico (12·55±0·10, 12·61±0·08, 12·75±0·10, 12·76±0·07 years). The timing of menarche in Oaxaca girls is similar to that for rural Mayans in Guatemala. Ages at menarche for urban Mexican girls are somewhat lower than those for girls of North-west European ancestry and of North American girls of European ancestry.