Age Of Menarche In Girls Research Articles

The study of pubertal stage and age of menarche in girls in Isfahan province, Iran.

The onset age of pubertal changes varies widely among girls and has undergone changes over time around the world. This study aimed to determine the age of onset of puberty in healthy Iranian girls living in Isfahan province. This cross- sectional study was conducted among 13,886 students aged 6-18 years. They were selected by multistage random cluster sampling from urban and rural areas of Isfahan province of Iran. Pubertal stage was determined according the 5-level Tanner stages proposed by Marshall and Tanner. Trained physicians determined the breast development through both visual inspection and palpation, in addition, mothers assessed their daughter's pubic hair growth using Tanner's Sexual Maturation Scale (SMS) by comparison to standard pictures. The data were analyzed by the status quo method. Probit regression analysis was used to evaluate the median age of onset for each characteristic including menarche, breast and pubic hair. A total of 13,886 healthy girls with mean age (SD) of 11.97 (2.9) were studied. Overall 6968 (50.2%) girls experienced menstruation with a median (95%CI) age of 12.05(11.88-12.21) years at its onset. The median age for onset of breast development was 9.89 (95% CI: 9.77 - 10.02) years and for onset of pubic hair development was 10.14 (95% CI: 9.88- 10.39) years. The 3rd percentile for breast stage 2 (B2) and pubic hair stage 2 (PH2) was 6.85 and 6.75 years, respectively, and the 97th percentile for B2 and PH2 was 12.94and 13.54 years, respectively. According to our findings, the onset of puberty before 6.85 years should be considered as precocious puberty for Iranian girls. Our study indicated the secular trend toward earlier menarche in girls. Nationally representative surveys and longitudinal studies are necessary to determine the exact age of puberty for future international comparisons.

Association between Changes in Menarcheal Age and Adolescent Idiopathic Scoliosis: An Analysis of 38,879 Patients over 20 Years.

Menarche has a significant impact on the progression of adolescent idiopathic scoliosis (AIS); however, studies in this area are insufficient. This study used large-scale school screening data to investigate the relationship between menarcheal age and AIS, especially the severity of scoliosis. Of 2,326,577 students who participated in school screening for scoliosis (SSS) in South Korea from 2001 to 2021, 38,879 girls with AIS, who experienced menarche, were included. Data including the patient's demographics, such as menarcheal age, Cobb angle, Risser stage, and the interval between menarche and the time of screening were retrieved from the SSS database. Pearson correlation coefficient was used to identify the changes in menarcheal age according to the birth year and to investigate the relationship between menarcheal age and each variable of interest. Based on the birth year, the mean menarcheal ages in girls with AIS from 1988 to 2008 demonstrated a steadily decreasing trend over time (r = -0.857, p < 0.001). Girls with AIS and late menarche demonstrated a higher Cobb angle at the time of screening (r = 0.095, p < 0.001). Other variables did not significantly correlate with menarcheal age. Based on the SSS, a large-scale school screening dataset, menarcheal age in girls with AIS demonstrated an ongoing downward trend in the recent 20 years in South Korea. Notably, girls with AIS and late menarche had a higher Cobb angle at screening. Our findings indicate the need for earlier screening of AIS in girls who have not undergone menarche.

Study of rs7759938, rs314280, and rs314276 Polymorphisms of LIN28B in Relation to Age at Menarche in Girls of Greek Descent.

Single-nucleotide polymorphisms in LIN28B, critical regulators of female growth and puberty, have been linked to age at menarche. We assessed the association of rs7759938, rs314280, and rs314276 with menarcheal age in girls of Greek descent. We reviewed the records of 248 girls who had their first menstruation before 18 years and who attended the Greek Departments of Pediatric Endocrinology from January 2021 to July 2023. Genotyping was performed by standard DNA-based methods. Association analyses involved both parametric and non-parametric tests. The average age of breast and pubic hair development was 9.95 years, and the age at menarche was 11.55 years. Menarche occurred ≤11 years (mean 10.24 years) in 108 girls (43.5%) and >11 years (mean 12.55 years) in 140 (56.5%). The girls' menarcheal age correlated significantly with that of their mothers (average 12.1 years, p-value < 0.0001, Spearman's r 0.350). The dominant rs7759938(TT) genotype was the most common (55.2%), followed by the dominant rs314276(CC) (53.2%) and dominant rs314280(TT) (14.5%) genotypes. There was no association between age at menarche and any of the polymorphism genotypes/alleles or between genotypes/alleles and birth weight, gestational week, mode of delivery, and maternal age at menarche. Future large sample studies are warranted to confirm these results.

Earlier Menarche in Greek Girls Born by Caesarean Section: A Case-Control Study.

Objectives: The purpose of this study was to report on the menarcheal age in girls of Greek origin and assess its potential associations with their demographic and perinatal data, as well as their maternal menarcheal age. Methods: In this case-control study, adolescent girls were recruited between September 2021 and September 2022 from two Pediatric Endocrinology Units, Aristotle University of Thessaloniki, Greece. Eligible participants included Greek girls up to the age of 18 years, with menarche and the absence of chronic disease or chronic medication use. Participants were divided into two groups, the early menarche group and the control group (menarche before or after 11 years of age, respectively). Data included participants' maternal menarcheal age, their chronological age, place of residence, anthropometric data (at recruitment) and perinatal data (birth order, gestational age, type of delivery, birth weight/length). Results: A total of 100 girls aged 7-17 years (mean age ± SD 12.51 ± 2.59 years) were included in this study. The mean ± SD menarcheal age of the total sample was 11.47 ± 1.55 years (median 11.20 years; range 7.50-16.25 years); 43% had early menarche (median menarcheal age 10.50 years; range 7.50-10.91 years), and 57% had menarche after age 11 (median menarcheal age 12.08 years; range 11.00-16.25 years). The caesarean section rate was significantly (p < 0.001) higher in girls with early menarche (83.7%) than controls, whereas other variables did not differ significantly between groups. Conclusions: This Greek sample demonstrated a relatively young age at menarche with a significant proportion of girls with early menarche; in the latter group, the rate of caesarian sections was significantly higher than controls.

Exposure to Particulate Matter Air Pollution and Age of Menarche in a Nationwide Cohort of U.S. Girls.

It remains unclear whether in utero and childhood exposure to air pollution affects pubertal development, particularly age of menarche in girls. The aim of this study was to determine whether residential ambient particulate matter (PM) exposure in utero and during childhood is associated with age of menarche. We studied 5,201 girls in the Growing Up Today Study 2 (2004-present) who were 10-17 y of age at enrollment (47.7% premenarchal; 52.3% postmenarchal). Exposure to three size fractions of PM [fine PM with aerodynamic diameter (), PM with aerodynamic diameters (), and PM with aerodynamic diameter ()] was assigned based on maternal residential address, updated every 2 y, using nationwide spatiotemporal models. We estimated average PM exposure in utero, and time-varying windows: annual average exposure in the prior 1 and 2 y and cumulative average from birth. Age of menarche was self-reported on three surveys administered in 2004, 2006, and 2008. We calculated hazard ratios (HR) for menarche for an interquartile range (IQR) increase in PM exposure using Cox proportional hazard models adjusting for potential confounders. Girls attained menarche at 12.3 y of age on average. In the adjusted model, higher residential exposure to ambient during all time windows was associated with earlier age of menarche. The HRs of menarche for each IQR () increase in exposure to during the in utero period, 1 y prior to menarche, and throughout childhood were 1.03 [95% confidence interval (CI): 1.00, 1.06], 1.06 (95% CI: 1.02, 1.10) and 1.06 (95% CI: 1.02, 1.10), respectively. Effect estimates for exposure were similar, albeit attenuated, for all time windows. exposure was not associated with age of menarche. Among a large, nationwide, prospective cohort of U.S. girls, higher exposure to and in utero and throughout childhood was associated with an earlier age of menarche. Our results suggest that and may have endocrine-disrupting properties that could lead to altered timing of menarche. https://doi.org/10.1289/EHP12110.

Oogenesis in Women: From Molecular Regulatory Pathways and Maternal Age to Stem Cells

It is a well-known fact that the reproductive organs in women, especially oocytes, are exposed to numerous regulatory pathways and environmental stimuli. The maternal age is one cornerstone that influences the process of oocyte fertilization. More precisely, the longer a given oocyte is in the waiting-line to be ovulated from menarche to menopause, the longer the duration from oogenesis to fertilization, and therefore, the lower the chances of success to form a viable embryo. The age of menarche in girls ranges from 10 to 16 years, and the age of menopause in women ranges from approximately 45 to 55 years. Researchers are paying attention to the regulatory pathways that are impacting the oocyte at the very beginning during oogenesis in fetal life to discover genes and proteins that could be crucial for the oocyte's lifespan. Due to the general trend in industrialized countries in the last three decades, women are giving birth to their first child in their thirties. Therefore, maternal age has become an important factor impacting oocytes developmental competence, since the higher a woman's age, the higher the chances of miscarriage due to several causes, such as aneuploidy. Meiotic failures during oogenesis, such as, for instance, chromosome segregation failures or chromosomal non-disjunction, are influencing the latter-mentioned aging-related phenomenon too. These errors early in life of women can lead to sub- or infertility. It cannot be neglected that oogenesis is a precisely orchestrated process, during which the oogonia and primary oocytes are formed, and RNA synthesis takes place. These RNAs are crucial for oocyte growth and maturation. In this review, we intend to describe the relevance of regulatory pathways during the oogenesis in women. Furthermore, we focus on molecular pathways of oocyte developmental competence with regard to maternal effects during embryogenesis. On the background of transcriptional mechanisms that enable the transition from a silenced oocyte to a transcriptionally active embryo, we will briefly discuss the potential of induced pluripotent stem cells.

Is there a secular trend regarding puberty in children with down syndrome?

There are very few studies on the age of onset and end of puberty in children with Down syndrome (DS). Also, data regarding the course of puberty in these children compared to their healthy peers is limited. Moreover, there is limited information regarding the effects of factors such as obesity and hypothyroidism on the puberty process in children with DS. Our aim in our study is to determine whether the pubertal development of children with DS differs from their healthy peers and from previous studies conducted with DS children. The medical records of DS children were examined retrospectively. The anthropometric measurements and the age of onset of pubertal stages, and menarche were recorded. The patients' age at puberty onset, the puberty processes, and age at menarche were compared with their healthy peers and previously published data on children with DS. Of the 140 Down syndrome patients followed in our clinic, 51 of whom with puberty constituted the study group. The mean age of onset of puberty was 10.3 ± 1.0 years in our group (10.0 ± 0.8 years for girls, 10.6 ± 1.2 years for boys, respectively). Obesity occurred in 46% of pubertal girls with DS. The age of menarche in girls with DS was 11.8 ± 0.7 years. The menarche age of girls with DS was significantly different from healthy girls. In the DS boys, only the Tanner V stage ages were different from the healthy children. True- precocious-puberty was detected in three children. Although breast development begins later in females with DS than in their healthy peers; menarche is detected earlier than in their peers and a tendency towards obesity in the whole population. While the age of pubertal onset was similar to healthy children in male patients, our findings suggest that their puberty duration is longer.

PENGETAHUAN, SIKAP DAN KESIAPAN SISWI SEKOLAH DASAR ISLAM DI SURAKARTA DALAM MENGHADAPI MENARCHE

Menarche is the first menstruation and is a marker for young women entering puberty. The average age of menarche for girls occurs in the range of 9-15 years. Lack of knowledge and negative attitudes related to menstruation will affect the readiness of students to face menarche. The objectives of this study were to identify the level of knowledge, attitudes, and readiness of students to face menarche and analyze the relationship between knowledge and attitudes towards readiness to face menarche at Ta'mirul Islam Elementary School Surakarta. This type of research is descriptive-analytic with a cross-sectional design, the sample in this study was 83 respondents. The sampling technique used purposive sampling. The research instrument used a knowledge, attitude, and readiness questionnaire. Informed consent was obtained from parental consent. Data analysis to answer the hypothesis using the chi-square analysis technique. The results of the univariate analysis showed that children's knowledge was sufficient (34.9%), positive attitude (74.04% of children), and 75.9% of readiness stated that they were ready to face menarche. The results of the bivariate analysis showed that there was a significant relationship between knowledge and readiness to face menarche and there was a significant relationship between attitudes and readiness to face menarche with a p-value 0.001. There is a relationship between knowledge and attitudes of SD Takmirul Islam students with readiness to face menarche.

Exposure to non-persistent pesticides and puberty timing: a systematic review of the epidemiological evidence

Numerous modern non-persistent pesticides have demonstrated estrogenic/anti-androgenic activity and have been classified as endocrine-disrupting chemicals (EDCs). Processes involved in puberty development are vulnerable to EDCs, such as compounds that interfere with the metabolism or activity of sex steroids. To conduct a systematic review of epidemiological studies on the relationship between early-life exposure to non-persistent pesticides and puberty timing and/or sexual maturation in girls and boys. A systematic search was carried out using MEDLINE and SCOPUS databases, including original articles published up to November 2020. Thirteen studies were selected after excluding non-original and non-human studies. Exposure to different types of pesticides has been associated with altered puberty timing in girls and/or boys in eight studies. In utero exposure to atrazine has been related to earlier age of menarche in girls; exposure to organophosphate (OP) pesticides has been related to delayed sexual development in boys and girls; childhood pyrethroid exposure has been associated with pubertal delay in girls and pubertal advancement in boys; and prenatal/childhood exposure to multiple pesticides has been linked to earlier puberty onset in girls and pubertal delay in boys. Most of the reviewed studies describe a relationship between pesticide exposure and changes in the age of puberty onset or sex hormone levels, although the quality of the evidence is generally low. Further well-designed longitudinal studies are warranted on specific classes of pesticides and on possible interactions between different types of compounds.

Menarche in adolescents from Vojvodina (the Republic of Serbia) in the period 2001-2019.

Objective:Menarcheal age is the starting point of reproductive life and could be a marker of health and socioeconomic status of a population.The aim of this study was to assess the temporal pattern in variability of menarcheal age from 2001 to 2019 and the relationship with biological factors and educational level of parents. Subjects and methods: A cross-sectional anthropometric survey was conducted in three intervals: 2001-2004, 2011-2014 and in 2019. In total, 5201 adolescent girls from Vojvodina (North Serbia) aged 11-18 were surveyed, 3272 (62.91%) of them with menarche. Data on the age at menarche was gathered applying status quo method and the age at menarche was calculated by probit analysis. The surveyed traits included height, weight and Body mass index (BMI). Results: Mean menarcheal age declined from 12.60 ± 1.11 years to 12.33 ± 1.20 years during the period from 2001 to 2019. Within three investigated periods variance decreased after the first decade from 1.23 year2 to 1.09 year2, and then increased to 1.44 year2. On average, postmenarcheal girls were 4.36 cm taller, 8.03 kg heavier, and their BMI was 1.96 kg/m2 higher than in premenarcheal girls of the same calendar age. An inverse effect of BMI and mother's education on the menarcheal age was detected, but the interaction between the variables was not statistically significant. Conclusion: These results indicate continuing decrease in menarcheal age in girls from Vojvodina. Menarche is closely associated with BMI and it appears that this factor effects the age at menarche irrespective of the parents' education.

The Study on Age of Menarche in Girls in the Buldana District of Maharashtra

The present study was designed to determine the age at which menarche occurs among school girls in Buldana district of Maharashtra state, India. A survey was conducted among 488 girls by writing the questionnaire from schools in the selected area. Respondents completed a questionnaire that recorded age at first menstruation by the recall, residential status, type of education, and diet/food habit. The mean age at menarche was 13.44 ± 0.75 years. Most girls (72.95%) of the respondents were found of normal age menarche (12–14 years), 27.05% of late-type menarche (&gt; 14 years), and 0% were of early menarche (less than 12 years). Our study suggests an influence of school education, residential area, and diet/food habit on menarcheal age.

The Association of Pornographic Media Exposure and Nutritional Status with Early Menarche

Introduction: The adolescent menarche period has shifted to a younger age because of several factors, including a girl’s nutritional status and exposure to pornographic media. The purpose of this study is to determine the relationship between pornographic media exposure and nutritional status with the age of menarche in girls in elementary school.Methods: This research used a descriptive cross-sectional design. 121 respondents were selected by proportional random sampling. Nutritional status data was collected by measuring body mass index, while the usage of media exposure and the age of menarche were both identified using questionnaires. All data was analysed using the chi-square test.Results: There was a significant relationship between the age of menarche with the exposure to mass media (p=0.000) and nutritional status (p=0.000).Conclusion: The age of menarche in adolescent girls is associated with nutritional status and media exposure.

Influence of socioeconomic factors during adolescence on the menarcheal age in Central Poland girls.

The purpose of the project was to indication the environmental factors that may influence on the menarcheal age in girls of Central Poland. The study was conducted in Warsaw and Lodz between 2016 and 2017 among subjects of randomly selected high schools, schools for adults, and workplaces. The material included 752 subjects between the ages of 16.00 and 29.23 years (mean age was 20.99 years). The questionnaire form provided information on the place of residence, parents' educational level, living conditions, and the number of children in the family. All questions concerned the period of adolescence. Studied subjects also were asked about their participation in sports in and outside the school, the level of stress at school and at home, smoking habits, and their age at menarche. To find the relation between the age at menarche and the socioeconomic status and living condition, the Generalized Linear Model with link function logit analysis and t-test were used. The statistically significant difference in the age at menarche was found based on the place of residence during adolescence and father's educational level. The girls from larger cities, whose fathers have higher education seem to mature earliest.

Thyroid-stimulating hormone is not the primary regulator of thyroid development in euthyroid children and adolescents living in an iodine-replete area.

It is known that there are multiple factors which can affect thyroid gland development during childhood and adolescence. Our aim was to investigate this issue by examining the relationships between age, sex, several anthropometric parameters, pubertal status, thyroid function tests, and iodine intake status with thyroid volume (TV) in children and adolescents. This was a cross-sectional field study conducted in 11 representative cities and villages of Uzbekistan. Six hundred and ten children and adolescents participated. Anthropometric indices and TV were estimated. In addition, thyroid function tests (TFTs) and urinary iodine excretion (UIE) measures were obtained. Median UIE was 151μg/L, thus the studied areas were iodine-sufficient. TFTs fluctuated in both genders during childhood and adolescence and the thyroid growth spurt was observed, in both sexes, at the ages of 12 and 13years, which coincided with the age of menarche in girls. Thyroid volume was positively correlated with body surface area (BSA) (r = 0.800, p < 0.001), age (r = 0.780, p < 0.001), fat-free mass (FFM) (r = 0.797, p < 0.001) and negatively correlated with serum TSH (r = -0.154, p = 0.05). No association between thyroid volume and UIE was observed. In euthyroid children and adolescents living in iodine-replete areas, thyroid gland development appears to follow the pattern of linear growth and displays a growth spurt at the onset of puberty, probably due to the abrupt increase of circulating sex steroids. At this age, TSH does not appear to be the main regulator of thyroid gland development.

External-environmental and internal-health early life predictors of adolescent development.

A wealth of evidence documents associations between various aspects of the rearing environment and later development. Two evolutionary-inspired models advance explanations for why and how such early experiences shape later functioning: (a) the external-prediction model, which highlights the role of the early environment (e.g., parenting) in regulating children's development, and (b) the internal-prediction model, which emphasizes internal state (i.e., health) as the critical regulator. Thus, by using data from the NICHD Study of Early Child Care and Youth Development, the current project draws from both models by investigating whether the effect of the early environment on later adolescent functioning is subject to an indirect effect by internal-health variables. Results showed a significant indirect effect of internal health on the relation between the early environment and adolescent behavior. Specifically, early environmental adversity during the first 5 years of life predicted lower quality health during childhood, which then led to problematic adolescent functioning and earlier age of menarche for girls. In addition, for girls, early adversity predicted lower quality health that forecasted earlier age of menarche leading to increased adolescent risk taking. The discussion highlights the importance of integrating both internal and external models to further understand the developmental processes that effect adolescent behavior.

Age at Menarche and its Relationship to Anthropometric Indices in Adolescent Girls

Background Menarche is a substantial and important period in the health of adolescent girls’, and has a significant impact on their health in the upcoming years. Accordingly, in this study, we aimed to not only determine the average age of menarche among high school girls in Qom city, but also to examine the effect of some factors on onset age of menarche. Materials and Methods In this cross-sectional study, a researcher-made questionnaire was presented to 400 girl students from six high schools in Qom city-Iran, including questions about individual characteristics, onset age of menarche in the participant and her mother, and some other indicators related to menarche. Data were analysis using SPSS version 16.0 software. Results From 400 distributed questionnaires 370 (92.5%) were filled correctly and completely. The findings of this study showed that the average age of menarche in girls has been 12.3 ± 1 year and 90% of the subjects had experienced menarche before the age of thirteen. Among the effective factors, a significant relationship was observed between daughters’ onset age of menarche and their mothers’ age (P < 0.01). Weight, Body mass index (BMI), and waist circumference (WC) was inversely and significantly associated age of menarche among the test subjects (P<0.01). Conclusion Based on the findings of this study, there was a high relationship between the onset age of menarche among the mothers and the daughters’ menarche age. Also, our results confirm that higher BMI, weight, and WC were negatively correlated to the age at onset of menarche.

Hubungan Antara Status Gizi (IMT) dengan Usia Menarche pada Remaja Putri Usia 13-14 Tahun di SMPN 1 Pace Kecamatan Pace Kabupaten Nganjuk

The average of menarche young women continoued to decline on average about 3-4 months every 10 years. The shift of the age of menarche to younger age can cause emotional stress, the risk of breast cancer, pregnancy is noy on purpose. The purpose of this research is to know the relationship between nutritional status with age of menarche in young women aged 13-14 years. The type of this research use cross sectional research design. Sampling technique of this research used proportional stratified random sampling which the research took a random strata in the population, for this research the reseacher using the lottery draw. The researcher abtained samples of 76 responden of total student population of 96. The analysis data of this research is Spearman Rank. The result of the analysis data shows that there is no relationship between nutritional status with age of menarche which the value tcount = 0,647 less than ttable = 1,995. For this research the researcher gives suggestion to the next researcher to develop the factor social media that can influence the age of menarche in girls forther.; Keywords : nutritional status, age of menarche, young women

Weak associations between pubertal development and psychiatric and behavioral problems

Pubertal development has been associated with adverse outcomes throughout adolescence and adulthood. However, much of the previous literature has categorized outcome variables and pubertal timing measures for ease of mean difference or odds ratio interpretation. We use a UK-representative sample of over 5000 individuals drawn from the Twins Early Development Study to extend this literature by adopting an individual differences approach and emphasizing effect sizes. We investigate a variety of psychiatric and behavioral measures collected longitudinally at ages 11, 14 and 16, for multiple raters and for males and females separately. In addition, we use two measures of pubertal development: the Pubertal Development Scale at each age, as well as the age of menarche for girls. We found that pubertal development, however assessed, was linearly associated with a range of psychiatric and behavioral outcomes; however, the effect sizes of these associations were modest for both males and females with most correlations between −0.10 and 0.10. Our systematic analysis of associations between pubertal development, and psychiatric and behavioral problems is the most comprehensive to date. The results showing linearity of the effects of pubertal development support an individual differences approach, treating both pubertal development and associated outcomes as continuous rather than categorical variables. We conclude that pubertal development explains little variance in psychiatric and behavioral outcomes (<1% on average). The small effect sizes indicate that the associations are weak and should not warrant major concern at least in non-clinical populations.

Pubertal breast development in primary school girls in Sokoto, North-western Nigeria

Background. There is wide variation in normal pubertal timing among various populations. Objectives. To determine the mean age of pubertal stages of breast development and menarche, and the influence of nutrition and ethnicity on pubertal onset in primary school girls in Sokoto, North-Western Nigeria. Methods. A cross-sectional study using a multistage random sampling design was conducted on 994 primary school girls in grades 3 - 6. Weight and height measurements and Tanner breast staging were done. Body mass index (BMI) was calculated, and a BMI-for-age percentile was used to categorise nutritional status. There were four major ethnic groups. P≤0.05 was taken as showing statistical significance. Results. The participants’ mean age was 10.23 years (standard deviation (SD) 1.70, range 6 - 15 years). Of the 994 girls, 628 (63.2%) were pre-pubertal, and 366 (36.8%) were pubertal. Of the latter, 158 (15.9%) were in breast stage 2, while 112 (11.3%), 70 (7.0%) and 26 (2.6%) were in breast stages 3, 4 and 5, respectively. The mean ages (SD; range) of pubertal onset and menarche were 10.50 (1.33; 8 - 13), and 12.67 (1.65; 11 - 15), years, respectively. The overnourished (overweight/obese) and Igbo ethnic group girls had early-normal pubertal onset ( p =0.006 and p =0.001, respectively). Conclusion. The mean ages of Tanner breast stages 1 - 5 and menarcheal age of girls in Sokoto, North-Western Nigeria, were within the age ranges reported worldwide. Pubertal onset was influenced by nutrition.

The effect of Exercise on the Age at Menarche in Girls at Guidance Schools of Shiraz, Iran

Background: Menarche is a woman’s first menstruation and is determined by multiple factors. Objectives: The aim of this study was to evaluate the effect of exercise on the age of menarche in girls at guidance schools of Shiraz, Iran. Patients and Methods: This cross-sectional study attempted to evaluate the effect of regular exercise on the age of menarche in relation to demographic data in 483 randomly selected girls from guidance school in Shiraz, Iran, using statistical analysis including independent t-test, variance analysis and linear regression tests. Results: Participants were divided in two groups including 181 and 302 athletic and non-athletic girls, respectively. A statistically significant difference was found in the mean age at menarche between athletic 12.4 ± 0.9 SD and non-athletic girls 12.1 ± 1.0 SD years (P = 0.003). Linear regression indicated that mother’s age (P = 0.049) and exercise (P = 0.001) both have significant association with age at menarche. Conclusions: The age at menarche for the athletic group was significantly delayed. Exercise and mother’s age were significantly associated with age at menarche, whereas no significant association was observed between age at menarche and weight, BMI, father’s age, and mother’s and father’s educational levels.