Reproductive Axis Maturation in the Early Post-Menarchal Years

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. We are also looking at girls who may have a condition called PCOS. 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 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 Girls at risk for PCOS age 8-14 who have a mom or sister with PCOS Girls with irregular menstrual cycles age 11-17.5 To compare with the girls, we are looking at women \>=18-34 years old with PCOS, Healthy women \>= 18-34 years old without PCOS, and Mothers of pediatric participants age 18-65 Design: Both parents or guardians 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. They have the option to provide DNA samples. 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. There are additional parts that participants may choose to be involved in depending on how involved they want to be. At home, participants will collect their urine daily to measure hormones. They will keep a d