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An Investigation of the Effect of Vitamin D Level During Frozen Embryo Transfer (FET) in IVF and Pregnancy Outcomes

Vitamin D Levels and Pregnancy Outcomes Following Frozen Embryo Transfer (FET) in the UAE

Status
Recruiting
Phases
Unknown
Study type
Observational
Source
ClinicalTrials.gov
Registry ID
NCT07681115
Acronym
VitD in FET
Enrollment
126
Registered
2026-07-02
Start date
2026-06-01
Completion date
2027-08-01
Last updated
2026-07-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

In Vitro Fertilization and Embryo Transfer, Vitamin D Insufficiency

Keywords

frozen embryo transfer cycle, Vitamin D

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.

Detailed description

Serum vitamin D3 has attracted growing research interest for its potential role in female reproductive physiology. While some studies associate sufficient vitamin D3 levels with improved IVF outcomes, others have failed to confirm this, leaving the evidence base contested. Despite this uncertainty, pre-In vitro fertilization (IVF) vitamin D screening and supplementation of insufficient patients has become widespread clinical practice. Evidence specific to frozen embryo transfer (FET) cycles remains particularly limited. Recent prospective studies found no significant difference in ongoing pregnancy, live birth, or implantation rates between vitamin D3-insufficient women receiving supplementation and vitamin D3-replete women who did not, underscoring the need for higher-quality, targeted research. While emerging data support a role for vitamin D in endometrial receptivity, it remains unclear whether correcting insufficiency prior to FET meaningfully improves reproductive success. To address these gaps, our study will evaluate the association between serum vitamin D3 levels on the day of FET and subsequent pregnancy and delivery outcomes at a UAE fertility center. Supplementation history and relevant clinical variables will be captured via patient questionnaire. Vitamin D status will be classified per International Society of Endocrinology guidance: deficient (\<20 ng/mL), insufficient (20-29 ng/mL), and sufficient (≥30 ng/mL). Given the high regional prevalence of vitamin D deficiency, this study is well-positioned to determine whether vitamin D status represents a modifiable determinant of reproductive success, with direct implications for clinical screening and management protocols in this population.

Interventions

OTHERNo Intervention: Observational Cohort

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

Sponsors

Fakih IVF Fertility Center
Lead SponsorOTHER

Study design

Observational model
COHORT
Time perspective
PROSPECTIVE

Eligibility

Sex/Gender
FEMALE
Age
18 Years to 40 Years
Healthy volunteers
No

Inclusion criteria

Inclusion: * 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). Exclusion: * 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.

Design outcomes

Primary

MeasureTime frame
Concentration of serum 25-hydroxyvitamin D levels measured on the day of FETVitamin D level tested on the day of FET.
Clinical pregnancy testFrom enrollment on day of FET to 1 month post FET

Secondary

MeasureTime frame
Live birth rate, miscarriage rate, and preterm birth rate.From enrollment to six weeks post partum

Countries

United Arab Emirates

Contacts

CONTACTDr. Lamiya Mohiyiddeen, MD, FRCOG
lamiya.mohiyiddeen@fakihivf.com+971543676002
CONTACTFatma Bathawab, PhD
fatma.bathawab@fakihivf.com+971585707393
PRINCIPAL_INVESTIGATORLamiya Mohiyiddeen, MD, FRCOG

Fakih IVF Abu Dhabi

PRINCIPAL_INVESTIGATORMichael Fakih, MD

Fakih IVF Abu Dhabi

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jul 16, 2026