Puberty

Background: Studies suggest that overweight girls may be developing breast tissue, and therefore starting puberty, earlier than normal weight girls. However, it is hard to distinguish breast tissue from fatty tissue. Researchers think that by using breast ultrasound, among other tests, they can do a better job of telling whether an overweight girl has breast tissue. This will help them understand if overweight girls are truly entering puberty before normal weight girls. Objective: To find out if overweight girls go through puberty earlier than normal weight girls. Eligibility: Healthy girls 8-14 years old who: * Are normal weight or overweight * Have some breast development * Have not started their first period Design: Parents of participants will be screened over the phone. Most participants will have 1 visit. However, they can choose to have multiple visits within 4 weeks. The visit will include: * Physical exam that includes examination of the breasts and genital area * Breast ultrasound: A small hand-held device will be passed back and forth over the chest. It uses sound waves to create a picture of the breast tissue. * Pelvic ultrasound: A small, handheld device will be passed back and forth over the lower belly. It uses sound waves to create a picture of the ovaries. * Urine and blood test * A special x-ray called a DXA to measure the amount of fat in the body: The participant will lie still on a table while the x-ray takes pictures of the body. X-ray of the hand: The picture will tell researchers how mature the participant s bones are. Participants may be asked to come back 6 months later to repeat these tests.

This longitudinal study is designed to test bidirectional relationships between preteen girls' mental health and social media experiences. We will explore how pubertal development and experiences of rejection influence these relationships.

This study explores how a physical activity program can affect hormone health and diabetes risk in girls ages 8-12 who may be at higher risk. The study aims to address: * Does the 'ActiveGirls' program meet the needs of girls and families in engaging them to increase physical activity? * What is the trend of markers of diabetes risk and puberty hormones over a 1-year period and how are these levels related to physical activity levels? Participants in this study will either: * Participate in a 'full' intensity intervention that includes educational messages (text/email) as well as health coaching visits to support physical activity over a 6 month period * Participate in a delayed 'lower intensity' intervention that includes only educational messages (text/email) * Participants in both groups will complete at-home activity monitoring, two study visits for check-ups and tests, and surveys

This study is testing whether improving health in girls during the prepubertal period may slow the onset of puberty. This study will focus on prepubertal girls who have a high weight status (at or above the 85th percentile for body mass index). Half of the girls who join the study will participate in a treatment program to reduce weight and improve lifestyle behaviors, and half of the girls will participate in a control condition. The frequency of pubertal onset will be compared across the groups. This research is important because girls who experience puberty at an earlier age are at risk for poor psychological and physical health. Girls in the treatment condition will participate in the Family Based Treatment (FBT) program, an established treatment for children who are overweight or obese. Families attend 20 weekly sessions (30 minutes each) over a 5-month period. Sessions are led by a trained interventionist and focus on healthy eating and physical activity behaviors. Girls in the control condition will receive their usual medical care through their pediatric care doctor or other care provider. Families will also receive educational handouts about 1 time per month, addressing topics related to healthy eating and physical activity behaviors. Families in both the treatment and control conditions will participate in assessments conducted at baseline and approximately 6-, 12-, 18-, 24-, 30-, and 36 months follow-up. These assessments are led by a data collector and include the measurement of height and weight, pubertal status, and health behaviors.

The purpose of this study is to determine if, in mid- to late pubertal girls with hyperandrogenism (HA), androgen-receptor blockade (spironolactone) alone normalizes sleep-wake luteinizing hormone (LH) pulse frequency (primary endpoint) and overall LH and follicle-stimulating hormone secretion (secondary endpoints).

The purpose of this study is to determine if, in mid- to late pubertal girls with hyperandrogenism, androgen-receptor blockade (spironolactone) improves the ability of progesterone to acutely reduce waking luteinizing hormone pulse frequency (primary endpoint).

The purpose of this study is two-fold. (1) We will determine if in mid- to late pubertal girls without hyperandrogenism (HA), progesterone (P4) acutely reduces waking luteinizing hormone (LH) frequency to a greater extent than sleep-associated LH frequency. (2) We will determine if in mid- to late pubertal girls with HA, P4 will acutely suppress waking LH frequency to a lesser degree than it does in girls without HA.

Early diabetic kidney disease (DKD) occurs in 50-70% of youth with type 2 diabetes (T2D) and confers high lifetime risk of dialysis and premature death. Youth-onset T2D typically manifests during or shortly after puberty in adolescents with obesity. Epidemiological data implicate puberty as an accelerator of kidney disease in youth with obesity and diabetes and the investigators posit that the link between puberty and T2D-onset may explain the high burden of DKD in youth-onset T2D. A better understanding of the impact of puberty on kidney health is needed to promote preservation of native kidney function, especially in youth with T2D.

Pubertal transition leads to enduring neuroendocrine changes along with changes in the epigenome. The prevalence of psychiatric disorders significantly increases in females compared to males after puberty. There is likely to be an interaction between epigenetics, hormones and neurophysiological processes during puberty, leading to the increased prevalence of mental disorders in females. This study aims to shed light on these interactions underlying the emerging sex differences after puberty. Specifically, it seeks to investigate the epigenetic modifications and subsequent changes in gene expression during the pubertal transition and their association with negative emotionality (e.g., acute stress response and depressive symptoms) at molecular, neuronal, subjective and physiological levels.

Establishment of regular menstrual cycles is a key component of reproductive maturation and a recognized vital sign for health and well-being. Irregular menstrual cycles are especially common for the first 2-3 years after an adolescent's first menstrual period (i.e., menarche), which delays the identification and diagnosis of early reproductive disturbances such as polycystic ovary syndrome (PCOS). The purpose of this research study is to determine whether the ovary can serve as a reliable predictor of normal or abnormal development by following the trajectory of ovarian morphology in conjunction with menstrual cyclicity using 3D transabdominal ultrasound imaging in a prospective cohort study of adolescents. A secondary objective is to identify potential environmental factors such as diet and the gut microbiome which influence the trajectory towards normal or abnormal reproductive development.

The COPENHAGEN School Study is a combined cross-sectional and longitudinal study of healthy Danish school children. This study will by clinical examinations and withdrawal of blood samples investigate whether age of pubertal onset is continuing to decline in Denmark over the past 15 years. Furthermore, we will investigate the mechanism driving earlier onset of puberty and the long term health risks of extremely early puberty using Danish registry data