Skip Navigation
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

CaREFREE: Nutrition and Menstruation

Calorie Restriction, Environment and Fitness: Reproductive Effects Evaluation Study

Studies Seeking Participants Icon Studies Seeking Participants Location icon Residents of North Carolina 18 - 28 Ages 18 - 28 Gender Icon Female Only
four women walking beside each other laughing.
  1. Home
  2. Studies
  3. CaREFREE: Nutrition and Menstruation
  4. Study Overview

We protect our registrants' privacy

Many women develop irregular menstrual cycles which may make it difficult to become pregnant and increase the risk of osteoporosis. Why do exercise and diet have this effect in some women but not others? This study will help us understand how nutrition, exercise, and the environment affect women's reproductive cycles.

Who Can Participate?

  • Healthy women between the ages of 18-28 living in the Raleigh-Durham-Chapel Hill area
  • Regular menstrual cycles for the past three months
  • Not using hormonal birth control
  • Never given birth
  • Not pregnant, breastfeeding, or planning on becoming pregnant for the duration of the study
  • Not dieting or actively trying to lose weight during the past three months

What Is Required?

  • 9-10 study visits over three to four months
  • Physical exam, blood, urine, and ovulation tests
  • Physical fitness and body composition assessments
  • Meal and exercise plan; nutritional shakes, bars, and cookies provided
  • Quick and easy tracking of your menstrual cycle
  • Self-provided transportation to NIEHS Clinical Research Unit in Research Triangle Park, North Carolina, and the University of North Carolina at Chapel Hill

Who Is Running the Study?

Lead Researcher

Janet E. Hall, M.D., M.S.

Janet E. Hall, M.D., M.S.

Tel 984-287-3647
Learn More About Janet E. Hall, M.D., M.S.

Janet E. Hall, M.D., M.S. is an internationally known clinician and clinical researcher. She received her Masters of Medical Sciences in exercise physiology and her M.D. and Internal Medicine training at McMaster University in Ontario, Canada. She completed her training in Endocrinology and Metabolism at Massachusetts General Hospital in Boston and rose to the rank of Professor of Medicine at Harvard Medical School. She had continuous NIH extramural grant funding until moving to the NIEHS intramural program in 2015. Hall was elected to the Association of American Physicians in recognition of her contributions to both the science and academics of medicine and, as a leader in the field, is a former President of the Endocrine Society.

Research Page

For More Information About This Study