The Investigation of Vitamin D and Menstrual Cycles Trial, the inVitD Trial: A Phase II Clinical Trial
Completed · Phase 2 · Has a placebo group
Conditions studied: Reproductive Issues
In brief
Background: About 1.5 million U.S. women of reproductive age are estimated to be infertile. Many more have difficulty getting pregnant. Menstrual cycles are an indicator of a woman's general health. Menstrual cycle changes may predict difficulties in getting pregnant. Researchers want to see what role vitamin D may play in menstrual cycle health. Objective: To examine the effect of vitamin D supplementation on the hormones that come from the brain and the ovary during a menstrual cycle. Eligibility: Women aged 19-40 who have spontaneous menstrual cycles (are not taking any hormones) less than 50 days in length. Design: Participants will fill out a screening survey about their demographics and health history. It will take 5-10 minutes to complete. Participants will have 3 study visits. Participants who have low vitamin D and move to Phase 2 will receive 50000 IU//week of vitamin D supplement. Participants who do not have low vitamin D will receive placebo. If they have low vitamin D, they will not get the placebo. They will take the capsules by mouth, once per week, for 3 menstrual cycles (or about 90 days). Participants will have physical exams. Their height, weight, body fat percentage, blood pressure, and waist-hip ratio will be measured. They will give blood samples. They will self-administer vaginal and oral swabs. Participants will keep a daily menstrual diary. They will do daily home ovulation testing. They will collect urine at home. Some women may collect menstrual blood at home. Participants will fill out an online survey. It will ask about their health, diet, and physical activity; birth control use; pregnancy history; menstrual cycle; smoking and drinking habits; education; and occupation. It will take 20-30 minutes to complete. Participation will last for four menstrual cycles (about 4 months).
Key facts
- Study ID
- NCT05050916
- Run by
- National Institute of Environmental Health Sciences (NIEHS)
- People needed
- 998
- Starts
- 2023-03-17
- Expected to finish
- 2024-06-27
- Last updated by the study team
- 2026-08-04
Who can join
Age: 19 and older, up to 40. Sex: female. Healthy volunteers: not accepted.
You may not qualify if…
- An individual who meets any of the following criteria will be excluded from participation in this study:
- No menstrual period in the last 50 days, or, a typical menstrual cycle length <16 or >49 days.
- Use of a vitamin D supplement for more than one month and on more than 15 days out of each month. Volunteers will be asked to check their supplement label for vitamin D content.
- Unwilling to abstain from taking non-study vitamin D supplements during the study or if already taking a medically-advised vitamin D supplement.
- Use of a calcium supplement (including certain antacids) and unwilling to abstain from taking a calcium supplement during the study.
- Known polycystic ovarian syndrome
- Depo-provera use in the previous 12 months
- Current use of any hormones, including birth control
- Current use of a hormonal intrauterine device (IUD)
- Current pregnancy or lactation, trying to become pregnant, or planning to try in the next four menstrual cycles or 5 months.
- History of seizure disorders
- Celiac disease
- Crohn s Disease
- Body mass index >35
- Aged <19 or > 40 years
- Presence of known contraindications for vitamin D supplementation, history of any of the following: calcium disorder or hypercalcemia, tuberculosis or granulomatous disease, metastatic bone disease, sarcoidosis, Williams syndrome, kidney disease (kidney stones, renal failure or dialysis, lupus nephritis)
- Known liver disease (cirrhosis)
- History of cancer other than skin cancer.
- History of anorexia nervosa, bulimia or an eating disorder
- Use within the past 60 days, of exogenous hormones
- Type 1 or Type 2 diabetes
- Known heart disease
- Gastric bypass surgery
- Unwilling or unable to complete study activities, e.g. collect daily urine specimens, have blood drawn, complete daily diaries, attend in person study visits
- Non-English speaking
Where it is running
- Henry Ford Health System — Detroit, Michigan, United States
- NIEHS Clinical Research Unit (CRU) — Research Triangle Park, North Carolina, United States
Full record on ClinicalTrials.gov
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