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

Официальное название

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

Обзор

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.

Подробное описание

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.

Вмешательства

• Другое No Intervention: Observational Cohort
  There are no interventions in this study. This is an observational cohort study.

Первичные конечные точки

• Concentration of serum 25-hydroxyvitamin D levels measured on the day of FET [Срок оценки: Vitamin D level tested on the day of FET.]
• Clinical pregnancy test [Срок оценки: From enrollment on day of FET to 1 month post FET]

Вторичные конечные точки (1)

• Live birth rate, miscarriage rate, and preterm birth rate. [Срок оценки: From enrollment to six weeks post partum]

Критерии участия

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.

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Нет

Дизайн исследования

Модель наблюдения

Когортное

Центры проведения

ОАЭ · 1 центр

• Fakih IVF Fertility Centre LLC — Abu Dhabi

Публикации

• 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 29149263
• 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
• 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 22275473
• 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 21646368
• 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 39829955
• 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): PMID 33293396
• 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 40277196

Идентификаторы

NCT: NCT07681115 · FAKIHIVF-2025-5 · DOH/ADHRTC/2025/1884

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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