Table 3.
Summary of key studies on vitamin D and IVF outcomes in PCOS.
| No | Authors/year/country | Study design | Sample size | Vitamin D characterization | Main outcome measures | Method(s) of vitamin D estimation | Key findings |
|---|---|---|---|---|---|---|---|
| 1 | Ko et al. (2022) (2), Hong Kong | Retrospective Analysis | Not stated | Serum 25(OH)D before ovarian stimulation | Cumulative live birth rate | Serum assay | Higher vitamin D levels correlated with increased live birth rates. |
| 2 | Hu et al. (2023) (3), China | Clinical & Lab Study | Not stated | Serum and follicular 25(OH)D3 | Granulosa cell proliferation, pregnancy | ELISA | Improved IVF outcomes via increased granulosa cell activity. |
| 3 | Piao et al. (2024) (8), China | Retrospective + Prospective | Not stated | Serum vitamin D | Pregnancy rates | Serum test | Positive association between vitamin D levels and pregnancy success. |
| 4 | Zhou et al. (2022) (4), China | Meta-Analysis of RCTs | 5 RCTs | Vitamin D supplementation | IVF success rate | Across multiple trials | Vitamin D supplementation improved IVF outcomes. |
| 5 | Omran et al. (2020) (14), Egypt | Observational | Not stated | Serum vitamin D | ICSI outcomes | Serum test | Higher vitamin D levels associated with better oocyte fertilization. |
| 6 | Dastorani et al. (2018) (10), Iran | RCT | Not stated | 50,000 IU biweekly for 8 weeks | Insulin sensitivity, AMH, lipid profile | Serum measurement | Improved insulin resistance and metabolic profile with supplementation. |
| 7 | Lerchbaum et al. (2021) (11), Austria | RCT | Not stated | 20,000 IU weekly for 24 weeks | LH/FSH ratio, AMH levels | Serum test | Lower LH/FSH ratio and increased FSH—potential fertility benefits. |
| 8 | Pagliardini et al. (2015) (12), Italy | Cross-sectional | 335 | Serum 25(OH)D | Vitamin D deficiency prevalence | Serum assay | 89% of IVF patients were deficient; linked to reduced pregnancy rates. |
| 9 | Wu et al. (2019) (13), USA | Cross-sectional | 157 | Serum 25(OH)D | Ovarian response, immune markers | Immunological & serum tests | Low vitamin D linked to pro-inflammatory immune profile & poor response. |
| 10 | Li et al. (2024) (9), China | Review & Experimental | Not stated | Vitamin D3 in follicular fluid | Follicular development | VDR expression analysis | Promotes granulosa cell proliferation and oocyte maturation. |
| 11 | Dabrowski et al. (2015) (53), Poland | Narrative Review | – | Review of existing evidence | Fertility-related mechanisms of Vitamin D | – | Vitamin D plays a multifaceted role in reproductive health; low levels associated with poor fertility outcomes. |
| 12 | Dastorani et al. (2018) Dastorani et al. (10), Iran | RCT | 56 women with PCOS | 50,000 IU/week Vitamin D for 8 weeks | Metabolic profiles, gene expression, IVF outcomes | ELISA | Vitamin D supplementation improved insulin metabolism markers and gene expression in IVF candidates. |
| 13 | Di Bari et al. (2021) (54), Italy | Review | – | Not applicable | Bone metabolism, fracture risk in PCOS | – | Low Vitamin D associated with bone risks in PCOS, indirectly impacting reproductive health. |
| 14 | Domingues et al. (2019) (55), Brazil | Case–Control | 20 PCOS, 20 oocyte donors | Endogenous Vitamin D in follicular fluid | Proteomic profile of FF | Mass spectrometry | Distinct protein expression related to Vitamin D observed in PCOS patients. |
| 15 | Farhangnia et al. (2024) (56), Iran | Narrative Review | – | Endometriosis and Vitamin D | Role in endometrial environment | – | Vitamin D deficiency associated with inflammation and poor endometrial receptivity. |
| 16 | Fernando et al. (2020) (57), Australia | Review | – | VDBP and pregnancy outcomes | Mechanisms in Vitamin D transport | – | VDBP levels affect Vitamin D bioavailability in pregnancy and IVF. |
| 17 | Grzeczka et al. (2022) (15), Poland | Review | – | Focus on ovarian follicle | Role in oocyte maturation | – | Vitamin D important for follicular development; deficiency impairs oocyte quality. |
| 18 | Hager et al. (2019) (58), Austria | Retrospective Cohort | 62 women | Incidental endometriosis and Vitamin D | Endometriosis prevalence | Serum 25(OH)D | Women with PCOS and endometriosis had lower Vitamin D levels. |
| 19 | Hu et al. (2020) (59), China | RCT protocol | – | Pre-IVF Vitamin D supplementation | IVF pregnancy rates | To be measured | Trial to assess Vitamin D before IVF in PCOS population. |
| 20 | Hu et al. (2023) (3), China | Prospective Cohort | 112 women with endometriosis | Serum 25(OH)D3 | IVF outcomes | ELISA | Higher Vitamin D levels linked with better IVF outcomes via granulosa cell proliferation. |
| 21 | Iervolino et al. (2021) (28), Italy | Review | – | Natural molecules incl. Vitamin D | Fertility in PCOS | – | Vitamin D proposed as adjunctive treatment in PCOS. |
| 22 | Irani et al. (2017) (29), USA | RCT | 60 women with PCOS | 50,000 IU Vitamin D biweekly | Serum VEGF, clinical PCOS symptoms | ELISA | Vitamin D reduced VEGF and improved symptoms in PCOS. |
| 23 | Jeon (2023) (30), Korea | Narrative Review | – | Vitamin D and AMH | Ovarian reserve, depression | – | Low Vitamin D linked to low AMH and higher depressive symptoms. |
| 24 | Kalyanaraman and Pal (2021) (17), USA | Review | – | Pathophysiology of PCOS | Vitamin D pathways | – | Emphasizes role of Vitamin D in insulin resistance and inflammation in PCOS. |
| 25 | Ko et al. (2022) (2), Hong Kong | Retrospective Cohort | 874 women | Serum 25(OH)D before IVF | Cumulative live birth rate | Immunoassay | Higher Vitamin D predicted higher cumulative live birth rates. |
| 26 | Kolcsar et al. (2024) (31), Hungary | Cross-sectional | 220 women | Serum 25(OH)D | AMH levels in non-PCOS IVF | Immunoassay | Vitamin D positively correlated with AMH. |
| 27 | Meng et al. (2023) (75), Hungary | Retrospective | 192 infertile women | Serum 25(OH)D | Hormonal status | LC–MS/MS | Lower Vitamin D linked with hormonal dysregulation. |
| 28 | Kotlyar and Seifer (2023) (33), USA | Review | - | IVF in PCOS | Overview of therapies | – | Vitamin D among adjuvant strategies. |
| 29 | Lerchbaum et al. (2021) (11), Austria | RCT | 180 PCOS women | 20,000 IU/week Vitamin D | Androgens, AMH | ECLIA | No significant effect found on AMH, but trend toward improved androgens. |
| 30 | Li et al. (2024) (9), China | Review | – | Vitamin D3 and follicle development | Ovarian physiology | – | Vitamin D supports folliculogenesis. |
| 31 | Luddi et al. (2016) (34), Italy | Prospective | 40 IVF patients | Endogenous Vitamin D in FF | Oxidative stress and IVF outcome | LC–MS/MS | Antioxidants and Vitamin D reduced oxidative stress in FF of aged women. |
| 32 | Maaherra Armstrong et al. (2023) (35), Sweden | Cross-sectional | 420 IVF patients | Serum 25(OH)D | Vitamin D insufficiency prevalence | Immunoassay | High prevalence of insufficiency; correlated with BMI and lifestyle factors. |
| 33 | Mancini et al. (2021) (36), Italy | Review | – | Oxidative stress and inflammation | PCOS mechanisms | – | Vitamin D modulates inflammatory and oxidative pathways in PCOS. |
| 34 | Meng et al. (2023) (37), China | Meta-analysis | 12 studies | Vitamin D supplementation | Clinical pregnancy and live birth rates | – | Supplementation improved pregnancy and live birth rates. |
| 35 | Mesinovic et al. (2020) (38), Australia | Cross-sectional | 51 PCOS patients | 25(OH)D and D metabolites | Androgen levels | LC–MS/MS | Vitamin D metabolites inversely correlated with androgens. |
| 36 | Morgante et al. (2022) (18), Italy | Review | – | Vitamin D and PCOS | Physiology and treatment | – | Supports Vitamin D role in PCOS pathophysiology and therapy. |
| 37 | Nandakumar et al. (2024) (5), UK | Cross-sectional | 108 women | Vitamin D status | Cardiovascular biomarkers | Immunoassay | Low Vitamin D associated with adverse CV biomarkers in PCOS. |
| 38 | Nandi et al. (2016) (39), USA | Review | – | Vitamin D and fertility | Mechanisms of action | – | Supports role in hormonal and metabolic regulation. |
| 39 | Omran et al. (2020) (14), Egypt | Prospective Cohort | 100 PCOS undergoing ICSI | Serum 25(OH)D | ICSI outcomes | ELISA | Higher Vitamin D levels associated with better fertilization and pregnancy rates. |
| 40 | Ota et al. (2023) (40), Japan | Cross-sectional | 207 infertile women | Serum 25(OH)D | Reproductive and immune markers | Immunoassay | Seasonal variations of Vitamin D influence immune markers. |
| 41 | Paffoni et al. (2019) (41), Italy | RCT Protocol | Planned N = 120 | 25(OH)D before/during ART | ART outcomes (pregnancy/live birth) | Serum assay (planned) | Study protocol to assess Vitamin D supplementation impact on ART outcomes. |
| 42 | Pagliardini et al. (2015) (12), Italy | Cross-sectional | 335 infertile women | Serum 25(OH)D | Prevalence of hypovitaminosis D | Immunoassay | High prevalence of Vitamin D deficiency; associated with infertility. |
| 43 | Piao et al. (2024) (8), China | Retrospective & Prospective | 357 PCOS patients | Vitamin D levels & supplementation | Pregnancy outcomes | Serum assay | Supplementation improved pregnancy rates in Vitamin D-deficient women. |
| 44 | Rogenhofer et al. (2022) (42), Germany | Retrospective Cohort | 482 IVF/ICSI patients | Seasonal serum 25(OH)D | AMH, ovarian response | Immunoassay | Seasonal variation in Vitamin D levels linked to AMH and IVF response. |
| 45 | Saeed et al. (2022) (1), India | Systematic Review | 12 studies | Vitamin D in treatment of OLP | Therapeutic effectiveness | - | Findings suggest potential role for Vitamin D, though not specific to IVF/PCOS. |
| 46 | Schroder-Heurich and Von Versen-Hoynck (76), Germany | Narrative Review | – | Vitamin D deficiency in fertility | Mechanistic insight | – | Highlights link between Vitamin D and reproductive hormones. |
| 47 | Shahrokhi et al. (2016) (44), Iran | Narrative Review | – | Vitamin D in reproduction | Follicular development and endometrial receptivity | – | Emphasizes role of Vitamin D in endometrial receptivity and fertility. |
| 48 | Shen et al. (2017) (45), China | Proteomic Analysis | 40 IVF patients | Vitamin D in follicular fluid | IVF success-related proteins | Mass spectrometry | Certain proteins related to Vitamin D status linked to IVF success. |
| 49 | Showell et al. (2018) (46), International | Cochrane Review | 10 RCTs | Inositol in PCOS | IVF outcomes, ovulation, live birth | – | Inositol may improve IVF outcomes; indirect support for Vitamin D adjuncts. |
| 50 | Singh et al. (2023) (47), India | Review | – | PCOS pathogenesis | Therapeutic strategies including Vitamin D | – | Supports Vitamin D as part of PCOS management due to anti-inflammatory effects. |
| 51 | Skowrońska et al. (2016) (48), Poland | Systematic Review | – | Vitamin D and reproductive dysfunction | Fertility and IVF outcomes | – | Low Vitamin D associated with reproductive dysfunction, especially in PCOS. |
| 52 | Sparic et al. (2024) (6), Serbia | Review | – | Vitamin D in PCOS | Clinical impact of Vitamin D | – | Clinical data support the link between Vitamin D status and PCOS symptoms. |
| 53 | Süli et al. (2023) (49), Hungary | Experimental Animal Study | Rat model of PCOS | Vitamin D supplementation in PCOS rats | Vascular reactivity | Serum 25(OH)D | Vitamin D had a protective vascular effect in a PCOS model, especially in females. |
| 54 | Vanni et al. (2014) (50), Italy | Review | – | Vitamin D in ART | ART outcomes, follicular development | – | Highlights positive associations of Vitamin D with ART success. |
| 55 | Várbíró et al. (2022) (16), Hungary | Review | – | Fertility, pregnancy, PCOS | Role of Vitamin D | – | Summarizes clinical and preclinical findings supporting Vitamin D’s role in fertility. |
| 56 | Wesselink et al. (2015) (51), USA | Narrative Review | – | Supplements in IVF | IVF outcomes | – | Discusses multiple supplements including Vitamin D as beneficial for IVF. |
| 57 | Wu et al. (2019) (13), USA | Observational | 103 IVF patients | Serum 25(OH)D | Ovarian response, inflammatory markers | ELISA | Vitamin D deficiency associated with poor ovarian response and pro-inflammatory profile. |
| 58 | Zhang et al. (2022) (52), China | Prospective Cohort | 1,062 couples | Serum Vitamin D before conception | Time to pregnancy, pregnancy outcomes | LC–MS/MS | Higher Vitamin D levels associated with shorter time to pregnancy and better outcomes. |
| 59 | Zhou et al. (2022) (4), China | Meta-analysis | 5 RCTs | Vitamin D supplementation | IVF outcomes | – | Supplementation improves clinical pregnancy rate and may reduce miscarriage risk. |