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The Investigation of Vitamin D and Menstrual Cycles Trial, the inVitD Trial: A Phase II Clinical Trial

NCT05050916 · Status: COMPLETED · Phase: PHASE2 · Type: INTERVENTIONAL · Enrollment: 57

Last updated 2026-02-13

No results posted yet for this study

Summary

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).

Conditions

  • Reproductive Issues

Interventions

DIETARY_SUPPLEMENT

Vitamin D

The High Dose Vitamin D arm will receive 50,000 IU/week of cholecalciferol. The Low Dose Vitamin D arm will receive 4,200 IU/week of cholecalciferol

OTHER

Placebo

Cellulose capsule

Sponsors & Collaborators

  • National Institute of Environmental Health Sciences (NIEHS)

    lead NIH

Principal Investigators

  • Anne Marie Z Jukic, Ph.D. · National Institute of Environmental Health Sciences (NIEHS)

Study Design

Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Model
PARALLEL

Eligibility

Min Age
19 Years
Max Age
40 Years
Sex
FEMALE
Healthy Volunteers
No

Timeline & Regulatory

Start
2023-03-17
Primary Completion
2024-06-07
Completion
2024-06-27

Countries

  • United States

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT05050916 on ClinicalTrials.gov