Vitamin D Deficiency Does Not Influence Reproductive Outcomes of IVF-ICSI: A Study of Oocyte Donors and Recipients

Vitamin D levels in couples undergoing in vitro fertilization treatment: lack of association with embryo quality or pregnancy rates

OBJECTIVE

To investigate the potential impact of vitamin D (VD) serum levels on couples going through in vitro fertilization treatment in terms of embryo quality and pregnancy rates.

DESIGN

A retrospective cohort study.

SETTING

A private human reproduction center.

PATIENT(S)

A total of 267 couples underwent intracytoplasmic sperm injections between January 2017 and March 2019.

INTERVENTION(S)

The couples were categorized into four groups on the basis of 25-hydroxy VD (25OHD) levels measured at the beginning of the stimulation protocol: group 1 with 25OHD levels ≥30 ng/mL for both women and men; group 2 with 25OHD levels <30 ng/mL for both; group 3 women with 25OHD levels <30 ng/mL and men with 25OHD levels ≥30 ng/mL; and group 4 with women with 25OHD level ≥30 ng/mL and men with 25OHD level <30 ng/mL.

MAIN OUTCOME MEASURE(S)

We consider the quantity and quality of embryos during the cleavage as well as blastocyst stages as primary outcomes. Correspondingly, the clinical pregnancy rate (CPR) was regarded as a secondary outcome.

RESULT(S)

Our findings revealed no significant correlations between the studied VD groups and the evaluated outcomes. This includes the quantity and quality of embryos during the cleavage and blastocyst stages, as well as the CPR. Primary analysis revealed a small but statistically significant difference in the duration of controlled ovarian stimulation between group 1 and group 2 (95% confidence interval, 0.07-3.04) and between group 1 and group 3 (95% confidence interval, 0.05-3.23).

CONCLUSION(S)

The present study found no correlation between the studied VD levels and the quantity as well as quality of cleavage or blastocyst stage embryos, nor did it show any impact on CPRs. Further well-designed, prospective studies are warranted to determine whether and how vitamin D affects reproductive outcomes.

Association Between Vitamin D Level and Clinical Outcomes of Assisted Reproductive Treatment: A Systematic Review and Dose-Response Meta-Analysis

The investigation about association between vitamin D level and clinical outcomes of assisted reproductive treatment showed various outcomes. This study aimed to review the correlation between vitamin D and outcomes of assisted reproductive treatment. The search was registered on the PROSPERO database (CRD42023458040). PubMed, Embase, Medline, ClinicalTrials.gov, and Cochrane databases were searched up to July 2023. Twenty-three observational studies were selected for meta-analysis. Comparing groups with deficient and 'insufficient + sufficient' vitamin D level, meta-analysis showed positive correlation between clinical pregnancy rate and vitamin D (OR 0.81, 95%CI: 0.70, 0.95, P = 0.0001). Comparing groups with 'deficient + insufficient' and sufficient vitamin D level, meta-analysis showed positive correlation between vitamin D and clinical pregnancy rate (OR 0.71, 95%CI: 0.55, 0.91, P = 0.006), vitamin D and live birth rate (OR 0.69, 95%CI: 0.54, 0.89, P = 0.003). Subgroup analysis did not show the source of high heterogeneity. No correlation was found in biochemical pregnancy rate, ongoing pregnancy rate, miscarriage rate and implantation rate. In dose-response meta-analysis, a nonlinear association was found between vitamin D levels and outcomes when levels are below approximately 24 ng/L. The study shows that vitamin D level is associated with clinical pregnancy rate and live birth rate. Low vitamin D level does not influence biochemical pregnancy rate, ongoing pregnancy rate, miscarriage rate and implantation rate. Furthermore, 24 ng/L may be a possible threshold of vitamin D concentration in assisted reproduction therapy.

The effect of calcitriol on the development and implantation capacity of embryos from hyper-stimulated mice

The evidence concerning the role of vitamin D (VD) in reproduction is still inconclusive. Calcitriol was given to superovulated female mice at the time of FSH injection (Group A), or at day 0.5 of pregnancy (Group B). The retrieved and cultured embryos were transferred to the uteri of pseudopregnant females. Ten animals from each group conceived naturally, and at day 7.5 of pregnancy, the implantation sites were counted. Serum hormone concentrations were determined by ELISA. The expression of CD70, PD-L1, OX-40L, and PIBF on extracellular vesicles (EVs) was tested by flow cytometry. Calcitriol treatment did not alter serum oestradiol concentrations, while 25(OH) D levels significantly decreased in both treated groups. Progesterone concentrations were significantly higher in group A and lower in group B than in the controls. On EVs produced by group B embryos PIBF, CD70, and OX-40L expression were significantly lower, while that of PD-L1 was significantly higher than that of controls. Calcitriol treatment decreased the fertilization rate in group A, and the blastulation rate of cultured embryos in group B, while the implantation capacity of the embryos was not affected, suggesting that depending on the time of administration, VD has an adverse effect on oocyte maturation and embryo development, but not on the implantation rates.

Prevalence of Vitamin D Insufficiency and Its Determinants among Women Undergoing In Vitro Fertilization Treatment for Infertility in Sweden

There is a lack of research on women with infertility in the northern latitudes, where vitamin D insufficiency is high. Therefore, this study aimed to assess the prevalence and determinants of vitamin D insufficiency (serum 25(OH)D concentration < 50 nmol/L) among women undergoing in vitro fertilization (IVF) treatment. Thus, 265 women scheduled for IVF/intracytoplasmic sperm injection (ICSI) between September 2020 and August 2021 at Sahlgrenska University Hospital in Gothenburg, Sweden, were included. Data on serum 25(OH)D concentration, vitamin D intake, and sun exposure were collected via questionnaires and blood samples. Approximately 27% of the women had 25(OH)D insufficiency, which was associated with longer infertility duration. The likelihood of insufficiency was higher among women from non-Nordic European countries (OR 2.92, 95% CI 1.03-8.26, adjusted p = 0.043), the Middle East (OR 9.90, 95% CI 3.32-29.41, adjusted p < 0.001), and Asia (OR 5.49, 95% CI 1.30-23.25, adjusted p = 0.020) than among women from Nordic countries. Women who did not use vitamin D supplements were more likely to have insufficiency compared with supplement users (OR 3.32, 95% CI 1.55-7.10, adjusted p = 0.002), and those who avoided sun exposure had higher odds of insufficiency compared to those who stayed "in the sun all the time" (OR 3.24, 95% CI 1.22-8.62, adjusted p = 0.018). Women with infertility in northern latitudes and those from non-Nordic countries who avoid sun exposure and do not take vitamin supplements have a higher prevalence of 25(OH)D insufficiency and longer infertility duration.

Vitamin D and in vitro fertilization: a systematic review

PURPOSE

Vitamin D (VD) action on calcium is well known, but its other properties, particularly in the human reproductive system, are not completely understood. This review aims at assessing the relationship between serum VD levels and IVF results.

METHODS

A systematic review was carried out using MEDLINE, EMBASE, LILACS, Google scholar, the CAPES journal portal, and the Cochrane Library, as well as the descriptors "vitamin D" and "fertilization in vitro." The review was conducted by two authors following the PRISMA recommendations between September 2021 and February 2022.

RESULTS

Eighteen articles were selected. Five of them showed a positive correlation between serum VD levels and IVF results, 12 lacked any association, and 1 exhibited a negative correlation. The 3 studies that assessed VD in the follicular fluid found a positive correlation between the serum and follicular levels. Non-Hispanic White patients seemed to suffer the consequence of vitamin D deficiency more than Asian patients. In one study alone in the VD-deficient group, there was a larger number of natural killer (NK) cells, B cells, a greater proportion of helper T cells/cytotoxic T cells (Th/Tc), and an association with a smaller number of mature oocytes.

CONCLUSION

The association between serum VD levels and the post-IVF pregnancy rate is uncertain. However, VD levels might be more relevant in the White than in the Asian ethnicity and in the number of aspiration follicles, and they could act in the immune system having an impact both on embryo implantation and on pregnancy.

Correlation between 25-hydroxy vitamin D levels in women and in vitro fertilization outcomes: A cross-sectional study

Background

Vitamin D has recently raised a great deal of controversy, not because of its traditional role of absorbing calcium and maintaining bone health, but because of its unconventional role as an endocrine factor and the extent of its impact when linked to its specific receptors (VDR) found in different tissues. Research has raced trying to find its different roles in those tissues and its association with different clinical or medical conditions, and among these cases, its role in reproductive functions and fertility in women, these studies conflicted between supporting and denying the role of vitamin D in reproductive function and rejecting this hypothesis according to the results of their study.

Materials and methods

The in vitro fertilization process allowed us to study the possible hypotheses, as this technique provides an opportunity to study the relationship between vitamin D levels with the in vitro fertilization outcomes, thus providing us with an idea of the relationship of vitamin D with fertility in women. In order to study this relationship, we designed our research as a cross-sectional study to confirm or deny this claim. Vitamin D was measured in the blood and in the follicular fluid for all cases using the electrochemiluminescence immunoassay (ECLIA) for the assay of total vitamin D, then IVF outcomes were compared with the levels of vitamin D in the blood.

Results

the levels of vitamin D are not related to the criteria of eggs such as the number of eggs and the maturity rate (MR) of eggs, but they are correlated in a statistically significant manner with the fertility rate (FR), and at the same time the levels of vitamin D in the blood were completely independent of the clinical pregnancy rate (CPR).

Conclusion

blood vitamin D levels will affect the FR when its levels in the blood drop below a specified value, vitamin D did not correlate with the CPR. In the long run, there is scope for more research projects on vitamin D. Future research could include case-control studies of patients on vitamin D supplementation, and the study of its correlation with IVF outcomes.

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Vitamin D deficiency affects various body functions including reproductive system in females.

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Appropriate levels of blood 25-hydroxy vitamin D affect the egg fertility rate, while it does not affect the maturity rate.

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Adequate levels of 25-hydroxy vitamin D are not associated with clinical pregnancy rates during in vitro fertilization.

Increasing vitamin D levels to improve fertilization rates in cattle

Recently, interest in supplementing vitamin D (Vit D) to improve aspects of health, mainly in human fertility, has emerged. Still, supplementation of Vit D above the minimum required levels has yet to be explored in cattle despite evidence for Vit D receptors in reproductive tissues. The objective of this study was to establish if a dose-response relationship exists between Vit D exposure and success of in vitro production (IVP) of embryos and, if acute supplementation of Vit D improves pregnancy rates during timed artificial insemination (TAI) of dairy cows. Cumulus-oocyte complexes (COCs) were obtained from ovaries acquired from a local abattoir and cultured in five different IVP treatments from three separate collections (Control, 50, 100, 150, and 200 ng/mL of 1,25(OH)2D3; n = 20-30 COCs/group). In Experiment 2, dairy breed cows (n = 100) were synchronized for TAI with the PresynchOvsynch protocol. Cows received 150,000 IU of Vit D (n = 48) or castor oil as control (n = 53) along with gonadotropin-releasing hormone (GnRH) 24 h before TAI. Serum samples were collected before and 24 h after treatment. A small cohort of cows (n = 4) received the same treatments in two separate cycles and follicular fluid (FF) was collected after 24 h for calcidiol (25OHD) analyses. Increased concentrations of Vit D resulted in decreased rates of maturation of COC (150 and 200 ng/mL vs. control and 50 ng/mL; P = 0.01). Supplementation with 50 ng/mL resulted in greater numbers of early blastocyst and blastocyst stage embryos (P < 0.009). Pregnancy at first breeding did not differ (P = 0.13) between groups, but serum 25OHD increased in treated females after 24 h (P = 0.002). The FF 25OHD levels were reflective of serum levels, however, the observed increase in the treatment cycle (P = 0.04) was parallel to an overall increase in serum 25OHD during the entire second cycle, likely due to increased environmental sunlight exposure (March, control vs. May, treatment). A similar increase in the serum 25OHD in the lactating commercial herd maintained in covered housing was not observed, although experiments were conducted during a similar timeframe. This herd had levels of 25OHD near the low end of sufficiency according to National Research Council (NRC) guidelines. We conclude mild Vitamin D supplementation with concentrations at the higher end of NRC guidelines can improve maturation rates of recovered COCs. However, longer term supplementation may be needed to appreciate any benefits on fertility.

100 YEARS OF VITAMIN D: Effect of serum vitamin D level before ovarian stimulation on the cumulative live birth rate of women undergoing in vitro fertilization: a retrospective analysis

OBJECTIVE

Vitamin D receptors are present in the female reproductive tract. Studies on the association between serum vitamin D level and pregnancy rate of in vitro fertilization (IVF) showed inconsistent results and focused on a single fresh or frozen embryo transfer cycle. The objective of our study was to evaluate if serum vitamin D level before ovarian stimulation was associated with the cumulative live birth rate (CLBR) of the first IVF cycle.

DESIGN

Retrospective cohort study.

METHODS

Women who underwent the first IVF cycle from 2012 to 2016 at a university-affiliated reproductive medicine center were included. Archived serum samples taken before ovarian stimulation were analyzed for 25(OH)D levels using liquid chromatography-mass spectrometry.

RESULTS

In total, 1113 had pregnancy outcome from the completed IVF cycle. The median age (25th-75th percentile) of the women was 36 (34-38) years and serum 25(OH)D level was 53.4 (41.9-66.6) nmol/L. The prevalence of vitamin D deficiency (less than 50 nmol/L) was 42.2%. The CLBR in the vitamin D-deficient group was significantly lower compared to the non-deficient group (43.9%, 208/474 vs 50.9%, 325/639, P = 0.021, unadjusted), and after controlling for women's age, BMI, antral follicle count, type and duration of infertility. There were no differences in the clinical/ongoing pregnancy rate, live birth rate and miscarriage rate in the fresh cycle between the vitamin D deficient and non-deficient groups.

CONCLUSIONS

Vitamin D deficiency was prevalent in infertile women in subtropical Hong Kong. The CLBR of the first IVF cycle in the vitamin D-deficient group was significantly lower compared to the non-deficient group.

Effect of Vitamin D Supplementation on In Vitro Fertilization Outcomes: A Trial Sequential Meta-Analysis of 5 Randomized Controlled Trials

Despite numerous studies indicating an imperative role of vitamin D for reproduction, the importance of vitamin D supplementation on in vitro fertilization (IVF) outcomes remains controversial. We therefore performed this meta-analysis to investigate the IVF outcomes of vitamin D supplementation in infertile women with vitamin D deficiency. We systematically searched PubMed, Embase and the Cochrane library for identifying all relevant studies published before August 2021. Pregnancy rate was defined as the primary outcome while good quality embryo, fertilization rate, ongoing pregnancy, and miscarriage were secondary outcomes. We used Review Manager 5.3 (RevMan) to conduct meta-analysis and examined the robustness of the primary outcome by trial sequential analysis. Five studies were included in the final analysis and it suggested that vitamin D supplementation was associated with improved chemical pregnancy rate (risk ratio [RR] = 1.53, 95% confidence interval [CI] = 1.06 to 2.20, p = 0.02) but not benefited in improving clinical pregnancy rate (RR = 1.34, 95% CI = 0.81 to 2.24, p = 0.25) and all secondary outcomes. Trial sequential analysis suggested further studies are needed to confirm this conclusion. We concluded that vitamin D supplementation should be prescribed to improve chemical pregnancy in infertile women with vitamin D deficiency and more studies are required to further confirm this finding.

Vitamin D in follicular development and oocyte maturation

Vitamin D (VD) is a secosteroid hormone synthesized predominantly in the skin upon UV light exposure, which can also be obtained from dietary sources. In target cells, the bioactive VD binds to specific VD receptor to regulate downstream transcription of genes that are involved in a wide range of cellular processes. There is an increasing recognition that the proper physiological levels of VD are critical for optimizing reproductive potential in women. The direct VD action in the ovary was first suggested in the 1980s. Since then, research has attempted to determine the role of VD in follicular development and oocyte maturation in animal models and clinical settings. However, data published to date are inconclusive due to the complexity in VD metabolism and the fact that VD actions are pervasive in regulating physiological functions in various systems, including the reproductive, endocrine and nervous systems that control reproduction. This review summaries in vitro, in vivo, and clinical evidence regarding VD metabolism and signaling in the ovary, as well as VD-regulated or VD-associated ovarian follicular development, steroidogenic function, and oocyte maturation. It is suggested that adequate animal models are needed for well-controlled studies to unravel molecular mechanisms of VD action in the ovary. For clinical studies, follicular development and function may be evaluated more effectively in a relatively homogeneous patient population under a well-controlled experimental design. A comprehensive understanding of VD-regulated folliculogenesis and oogenesis will provide critical insight into the impact of VD in female reproductive health.

How vitamin D level influences in vitro fertilization outcomes: results of a systematic review and meta-analysis

OBJECTIVE

To investigate the impact of serum vitamin D level on in vitro fertilization (IVF) outcomes.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENTS

Infertile women undergoing conventional IVF or intracytoplasmic sperm injection (ICSI).

INTERVENTIONS

Systematic search of PubMed, MEDLINE, EMBASE, Global Health, The Cochrane Library, Health Technology Assessment Database, and Web of Science from inception until July 2019 with cross-checking of references from relevant articles in English. Vitamin D levels were categorized into three groups: deficient (<20 ng/mL), insufficient (20-30 ng/mL), and replete (>30 ng/mL). Before starting the data extraction, we registered the review protocol in PROSPERO (CRD42019134258).

MAIN OUTCOME MEASURES

We consider clinical pregnancy rate (CPR), live birth rate (LBR), and/or ongoing pregnancy rate (OPR) as primary outcomes. Likewise, the miscarriage rate was considered as a secondary outcome.

RESULTS

Primary analysis showed that women with a replete level of vitamin D had higher CPR and LBR/OPR compared to those with a deficient of insufficient level of vitamin D. However, sensitivity analysis led to non-significant differences between the comparators for CPR (odds ratio 0.71, 95% confidence interval 0.47-1.08, I2 = 61%) and OPR/LBR (odds ratio 0.78, 95% confidence interval 0.56-1.08], I2 = 61%). Also, for miscarriage a statistically different rate was not reached.

CONCLUSION

Serum vitamin D levels do not influence IVF outcomes in terms of CPR, LBR/OPR, and miscarriage rate. Future large cohort studies are warranted to determine whether the threshold of vitamin D affects reproductive outcomes. Currently, there is a lack of consensus between the appropriate vitamin D threshold to predict reproductive outcomes compared to the one established for bone health.

PROSPERO NUMBER

CRD42019134258.

Calcitriol Effect on Outcomes of in Vitro Fertilization in Infertile Women with Vitamin D Deficiency: A Double-Blind Randomized Clinical Trial

INTRODUCTION

Recent studies have addressed the role of micronutrients in fertilization, such as vitamin D. The present study aims to explore the effects of using calcitriol, an active form of vitamin D, on IVF results in women with vitamin D deficiency.

METHOD

This double-blinded randomized clinical trial was done on 180 infertile women, undergone IVF treatment. Out of them, 95 were found to have vitamin D deficiency (blood serum 25-dihydroxy vitamin D <30 ng/ml). Fifty one women in experimental group were treated with two 0.25 µg calcitriol pills daily during 4 weeks (discontinued 8 hours prior to the embryo transfer) and 44 subjects to the placebo group (mean vitamin D deficiency 27.5 ±1.8 in case group vs. 27.6±1.8 in control group, P>0.05). Final analysis includes outcomes of chemical and clinical pregnancy was done on 74 women (including 36 in case and 38 in control group).

RESULTS

Our study showed that in the experimental group, chemical pregnancy success was significantly higher than that in the control group, 31.4 vs. 18.2% (P<0.05). However, there were no significant differences between the 2 groups in reaching the clinical pregnancy stage (25.5% in case group vs. 13.6% in control group) and continuation of pregnancy into week 20 (9.8% in case group vs. 11.6% in control group) (P>0.05).

CONCLUSION

Calcitriol administration by improving the implantation process can significantly increase the chances of successful IVF cycle results in infertile women with vitamin D deficiency.

Female infertility: which role for obesity?

Obesity is associated with infertility in women through multiple and complex mechanisms. Briefly, the adipose tissue through the production of many factors, such as leptin, free fatty acids (FFA), and cytokines may affect both ovarian and endometrium functions, with a final alteration in oocyte maturation and endometrial epithelium receptivity. In addition, through the development of peripheral insulin resistance obesity produces a condition of functional hyperandrogenism and hyperestrogenism that contribute to produce anovulation and to reduce endometrial receptivity and, therefore participate to cause infertility. Weight loss is able to restore fertility in most cases, but there are no practical indications to guide the clinician to choice the best method among increased physical activity, diet, drugs, and bariatric surgery.

Vitamin D level affects IVF outcome partially mediated via Th/Tc cell ratio

PROBLEM

The role of vitamin D (VD) in IVF outcome and immune parameters has not been elucidated well.

METHOD OF STUDY

Women undergoing IVF treatment with GnRH agonist (Agonist) and progestin-primed ovarian stimulation (PPOS) protocols were divided into VD lower (VDL, 25(OH)VD ≤20 ng/mL) and VD higher (VDH, 25(OH)VD >20 ng/mL) groups. Follicular fluid (FF) VD level, IVF outcomes, and peripheral blood immunophenotypes by flow cytometry were analyzed.

RESULTS

FF VD levels of the whole subjects were positively correlated with peripheral blood VD level (r = 0.86, P < 0.001). The number of mature oocytes and the blastocyst formation rate were significantly higher in women with VDH group as compared with those of VDL group in both Agonist and PPOS groups (P < 0.05, respectively). In women with PPOS protocol, peripheral blood NK and B-cell proportions and T helper/T cytotoxic (Th/Tc) cell ratios of VDL group were significantly higher than those of VDH group (P < 0.05, respectively). In women with Agonist protocol, peripheral blood B-cell proportion and Th/Tc ratios of VDL group were significantly higher than those of VDH group (P < 0.05, respectively).

CONCLUSION

VD level is associated with IVF outcomes possibly derived by T-cell immunity, particularly Th/Tc ratios.

The role of female obesity on in vitro fertilization outcomes

The aim of this review is to analyze the role of obesity on fertility outcome in women undergoing in vitro fertilization (IVF) with respect to clinical or live birth rates and pregnancy loss rates. Despite findings from several earlier and newer studies that obesity does not adversely affect pregnancy outcome in women attempting conception, numerous reports from mostly recent studies suggest that obesity undoubtedly impairs IVF outcomes. Obesity impairs ovarian responsiveness to gonadotrophin stimulation, requiring higher doses of medication, increased risk of cycle cancelation, pre-term delivery, low birth weight or miscarriage, and decreases implantation, clinical pregnancy or live birth rates compared to women of normal weight. The mechanisms underlying the adverse effects of female obesity on IVF outcome may be primarily explained by functional alterations to the hypothalamic-pituitary-ovarian axis. Additionally, obesity appears to affect deleteriously the number and quality of oocytes or embryos, and impairs endometrial decidualization which is necessary for uterine receptivity. Nevertheless, attaining normal body weight by the use of lifestyle modifications, including a healthy diet and exercise over time of several months before and during an IVF treatment, may be successful in achievement of gradual and sustainable weight loss with improvement of IVF outcome.