NCT07681115

Brief Summary

Vitamin D is best known for keeping our bones healthy, but growing research suggests it may also play a role in fertility. Many In vitro fertilization (IVF) clinics now routinely check vitamin D levels and prescribe supplements before treatment, but the science is still unclear on whether this actually improves the chances of pregnancy. Our study, based in the United Arab Emirates (UAE), aims to find out whether a woman's vitamin D level on the day of her frozen embryo transfer (FET) makes a difference to whether she becomes pregnant and delivers a baby. The UAE is an ideal setting for this research, as vitamin D deficiency is particularly common in the region. The findings could shape how fertility clinics screen and treat women seeking fertility treatment in the future.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
126

participants targeted

Target at P50-P75 for all trials

Timeline
12mo left

Started Jun 2026

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress14%
Jun 2026Aug 2027

Study Start

First participant enrolled

June 1, 2026

Completed
25 days until next milestone

First Submitted

Initial submission to the registry

June 26, 2026

Completed
6 days until next milestone

First Posted

Study publicly available on registry

July 2, 2026

Completed
11 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

June 1, 2027

Expected
2 months until next milestone

Study Completion

Last participant's last visit for all outcomes

August 1, 2027

Last Updated

July 15, 2026

Status Verified

July 1, 2026

Enrollment Period

1 year

First QC Date

June 26, 2026

Last Update Submit

July 13, 2026

Conditions

Vitamin D InsufficiencyIn Vitro Fertilization and Embryo Transfer

Keywords

frozen embryo transfer cycleVitamin D

Outcome Measures

Primary Outcomes (2)

  • Concentration of serum 25-hydroxyvitamin D levels measured on the day of FET

    Vitamin D level tested on the day of FET.

  • Clinical pregnancy test

    From enrollment on day of FET to 1 month post FET

Secondary Outcomes (1)

  • Live birth rate, miscarriage rate, and preterm birth rate.

    From enrollment to six weeks post partum

Study Arms (1)

Women undergoing frozen embryo transfer (FET) at Fakih IVF

The study will enroll women aged 18-40 years with a BMI of 18-40 kg/m² undergoing FET at Fakih IVF, who had serum vitamin D assessed within three months prior to transfer. Women with deficient levels (\<30 ng/mL) must have received supplementation prior to FET to be eligible. Exclusions are designed to reduce confounding: women are excluded if vitamin D was not measured within the required window, if identified deficiency went untreated, or if they have a history of recurrent implantation failure (RIF). Women with uterine factors known to impair implantation including congenital anomalies, intrauterine adhesions, or submucosal fibroids are also excluded, as are those with significant medical comorbidities that may independently affect pregnancy outcomes.

Other: No Intervention: Observational Cohort

Interventions

No Intervention: Observational CohortOTHER

There are no interventions in this study. This is an observational cohort study.

Women undergoing frozen embryo transfer (FET) at Fakih IVF

Eligibility Criteria

Age18 Years - 40 Years
Sexfemale(Gender-based eligibility)
Gender Eligibility DetailsBiological female
Healthy VolunteersNo
Age GroupsAdult (18-64)
Sampling MethodNon-Probability Sample
Study Population

Women undergoing FET cycle who do not suffer from conditions affecting implantation and have got vitamin D levels tested 3 - 6 months before FET cycle.

You may qualify if:

  • Women undergoing frozen embryo transfer (FET) at Fakih IVF.
  • Age between 18 and 40 years.
  • Body mass index (BMI) between 18 and 40 kg/m².
  • Patients who had serum vitamin D levels assessed within three months prior to FET
  • Supplementation with Vitamin D if deficient \< 30 ng/mL (75 nmol/L).

You may not qualify if:

  • Age below 18 years or above 40 years.
  • BMI below 18 kg/m² or above 40 kg/m².
  • Patients who did not have vitamin D levels measured within three months prior to FET.
  • Patients who were found to have low vitamin D levels but did not receive supplementation.
  • Patients with recurrent implantation failure (RIF).
  • Patients with known uterine factors affecting implantation (e.g., congenital uterine anomalies, intrauterine adhesions, submucosal fibroids).
  • Patients with significant medical comorbidities that may affect pregnancy outcomes.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Fakih IVF Fertility Centre LLC

Abu Dhabi, United Arab Emirates

RECRUITING

Related Publications (7)

  • Chu J, Gallos I, Tobias A, Tan B, Eapen A, Coomarasamy A. Vitamin D and assisted reproductive treatment outcome: a systematic review and meta-analysis. Hum Reprod. 2018 Jan 1;33(1):65-80. doi: 10.1093/humrep/dex326.

    PMID: 29149263BACKGROUND

  • Anifandis, G., Dafopoulos, K., Messini, C. I., et al. (2021). The impact of vitamin D supplementation on reproductive outcomes in infertile women: A systematic review and meta-analysis. Hormones (Athens), 20(2), 145-154. https://doi.org/10.1007/s42000-021-00291-1

    BACKGROUND

  • Lerchbaum E, Obermayer-Pietsch B. Vitamin D and fertility: a systematic review. Eur J Endocrinol. 2012 May;166(5):765-78. doi: 10.1530/EJE-11-0984. Epub 2012 Jan 24.

    PMID: 22275473BACKGROUND

  • Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM; Endocrine Society. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011 Jul;96(7):1911-30. doi: 10.1210/jc.2011-0385. Epub 2011 Jun 6.

    PMID: 21646368BACKGROUND

  • Wang K, Dong F, Ma S, Bu Z. The association between Vitamin D deficiency and clinical pregnancy rate in IVF patients with different age. Front Endocrinol (Lausanne). 2025 Jan 3;15:1485238. doi: 10.3389/fendo.2024.1485238. eCollection 2024.

    PMID: 39829955BACKGROUND

  • Hu KL, Gan K, Wang R, Li W, Wu Q, Zheng B, Zou L, Zhang S, Liu Y, Wu Y, Chen R, Cao W, Yang S, Liu FT, Tian L, Zeng H, Xu H, Qiu S, Yang L, Chen X, Pan X, Wu X, Mol BW, Li R, Zhang D. Vitamin D supplementation prior to in vitro fertilisation in women with polycystic ovary syndrome: a protocol of a multicentre randomised, double-blind, placebo-controlled clinical trial. BMJ Open. 2020 Dec 8;10(12):e041409. doi: 10.1136/bmjopen-2020-041409.

    PMID: 33293396BACKGROUND

  • Christoforidis N, Papapanou M, Michalakis D, Dimitraki M, Chatziparasidou A, Siristatidis C. Effect of vitamin D supplementation on frozen embryo transfer cycle outcomes. Hum Fertil (Camb). 2025 Dec;28(1):2493251. doi: 10.1080/14647273.2025.2493251. Epub 2025 Apr 25.

    PMID: 40277196BACKGROUND

Study Officials

  • Lamiya Mohiyiddeen, MD, FRCOG

    Fakih IVF Abu Dhabi

    PRINCIPAL INVESTIGATOR

  • Michael Fakih, MD

    Fakih IVF Abu Dhabi

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Dr. Lamiya Mohiyiddeen, MD, FRCOG

CONTACT

+971543676002lamiya.mohiyiddeen@fakihivf.com

Fatma Bathawab, PhD

CONTACT

+971585707393fatma.bathawab@fakihivf.com

Study Design

Study Type
observational
Observational Model
COHORT
Time Perspective
PROSPECTIVE
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

June 26, 2026

First Posted

July 2, 2026

Study Start

June 1, 2026

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

August 1, 2027

Last Updated

July 15, 2026

Record last verified: 2026-07

Data Sharing

IPD Sharing
Will not share

Not an NIH project

Locations

AE(1)