Background:

Most adult women with irregular periods of unknown cause report symptoms dating back to early adolescence. This study aims to learn how girls periods change in the 2 years after their first period. This will help researchers learn what healthy puberty looks like and how they can spot signs of hormone problems early on.

Objective:

To learn how long it takes girls to develop regular menstrual cycles after their first period.

Eligibility:

Healthy girls ages 8-14.5 who either (1) haven t had their first period but show signs of puberty, such as breast development and hair in the genital area; or (2) had their first period in the past 6 months

Design:

A parent or guardian must allow their daughter to participate. They must attend all study visits with her.

Participants will first be screened by phone. Those who qualify will be screened in person. They will have a physical exam. They will give blood and urine samples. They will have an ultrasound of their abdomen. They will fill out questionnaires. They will sit in a BOD POD for 6 minutes: This is an egg-shaped machine that takes body measurements.

Participants will have sets of visits at home or at the clinic about every 6 months. The number of visits in each set will depend on their menstrual cycle. Then they will have a final visit. Visits will include repeats of the screening tests.

At home, participants will collect their urine daily to measure hormones. They will keep a diary of their periods.

The study will last about 2 years.

• Reproductive Physiological Processes
• Pediatrics
• Adolescent Health
• Adolescent Developement

• Part 1-Pre-menarche monitoring (holding pattern):

INCLUSION CRITERIA:

• Age 8-14.5 years old
• Healthy weight, defined as having a body weight >85% of expected (EBW) and a body mass index (BMI) <99th percentile
• Some breast development
• Pre-menarche

EXCLUSION CRITERIA:

• Taking or planning to take medications that affect reproductive hormones in the next 2 to 3 years (e.g. birth control pills).
• Planning to move more than 60 miles from the CRU within the next 2 years
• Chronic medical condition, including but not limited to diabetes mellitus, congenital adrenal hyperplasia, cystic fibrosis, sickle cell disease, inflammatory bowel disease, juvenile rheumatoid arthritis, and lupus.
• First-degree relative with polycystic ovarian syndrome, premature ovarian insufficiency, hypogonadotropic hypogonadism, or other pubertal development disorder
• Excessive exercise (defined as running >20 miles per week or its equivalent)
• Pregnancy

Part 2 - Post-menarche cycle tracking:

INCLUSION CRITERIA:

• Age at menarche 10-14.5 years old
• Healthy weight, defined as having a body weight >85% of expected (EBW) and a body mass index (BMI) <99th percentile
• Approximately less than or equal to 6 months post-menarchal (will typically have completed 4 or fewer menstrual cycles)

Biochemical criteria: normal thyroid hormone, prolactin, and testosterone levels

EXCLUSION CRITERIA:

• Taking or planning to take medications that affect reproductive hormones in the next 2 to 3 years (e.g. birth control pills).
• Planning to move more than 60 miles from the CRU within the next 2 years
• Chronic medical condition, including but not limited to diabetes mellitus, congenital adrenal hyperplasia, cystic fibrosis, sickle cell disease, inflammatory bowel disease, juvenile rheumatoid arthritis, and lupus.
• First-degree relative with polycystic ovarian syndrome, premature ovarian insufficiency, hypogonadotropic hypogonadism, or other pubertal development disorder
• Excessive exercise (defined as running >20 miles per week or its equivalent)

• Anemia (defined as hemoglobin <12.0 g/dl)

  --Participants with hemoglobin between 11.5 g/dl and 12.0 g/dl may still participate by providing dried blood spots, or no more than 18ml of blood during any given interval.

• Pregnancy

In some cases, particularly in those participants with short menstrual cycle lengths, the participant may have her first cycle monitoring visit before the results from all the laboratory tests from the screening visit are available. Some of these tests take > 5-7 days to complete. The tests are necessary for eligibility but are not related to participant safety. If the results are abnormal, the participant will be withdrawn from the study at that time.

If a potential participant meets all eligibility criteria for Part 1 during the initial phone screening, she and at least one parent or guardian will verbally assent and consent, respectively, to receive regular communications from the study team (i.e. monthly phone calls, emails, and text messages. The purpose of these communications is follow-up with the participant to determine when she can enroll in Part 2 of the study. She will not participate in any clinical study procedures in Part 2 as detailed below until she has her first period, at which time she and/or her parent or guardian will notify the study team. This will allow study staff to enroll girls at the desired (young) gynecological age and allow initial study visits to be scheduled in alignment with the girls' menstrual cycles.