The Investigation of Vitamin D and Menstrual Cycles Trial, the inVitD Trial: A Phase II Clinical Trial
Public ClinicalTrials.gov record NCT05050916. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Official title
The Investigation of Vitamin D and Menstrual Cycles Trial: A Phase II Clinical Trial
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
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).
Study identification
- NCT ID
- NCT05050916
- Recruitment status
- Completed
- Study type
- Interventional
- Phase
- Phase 2
- Enrollment
- 998 participants
Conditions and interventions
Conditions
Eligibility (public fields only)
- Age range
- 19 Years to 40 Years
- Sex
- Female
- Healthy volunteers
- Healthy volunteers not accepted
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Mar 16, 2023
- Primary completion
- Jun 6, 2024
- Completion
- Jun 26, 2024
- Last update posted
- Aug 31, 2026
2023 – 2024
United States locations
- U.S. sites
- 2
- U.S. states
- 2
- U.S. cities
- 2
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| Henry Ford Health System | Detroit | Michigan | 48187 | — |
| NIEHS Clinical Research Unit (CRU) | Research Triangle Park | North Carolina | 27709 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT05050916, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Aug 31, 2026 · Synced Sep 6, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT05050916 live on ClinicalTrials.gov.