The interaction between thyroid function and ovarian activity constitutes a pivotal element in the pathophysiology of female fertility. Thyroid dysfunctions, including subclinical forms, can impair fundamental reproductive mechanisms such as folliculogenesis, ovulation, and embryo implantation. In this context, growing attention is focused on the role of iodine, an essential micronutrient for thyroid hormone synthesis and a key determinant in maintaining endocrine-reproductive balance. Recent evidence suggests that iodine may exert a direct influence on ovarian reserve and, consequently, on the outcomes of Assisted Reproductive Technology (ART), highlighting the importance of a comprehensive assessment of thyroid and nutritional status in fertility management. This study aims to investigate the role of iodine status in female reproductive function within a population of infertile women undergoing ART pathways. Specifically, the objective is to investigate potential correlations between iodine status (estimated via urinary iodine concentration, UIC), thyroid function, and ovarian reserve. Furthermore, it aims to analyze these associations within the dynamic context of controlled ovarian stimulation (COS), evaluating the relationship between urinary iodine levels and the primary clinical outcomes of ART. Lastly, the study seeks to contextualize patients' iodine status in relation to their dietary habits, in order to explore potential nutritional determinants of iodine intake and their impact on reproductive outcomes. This single-center observational study was conducted at the ART Unit of the University Hospital of Padua. The sample included women diagnosed with infertility, for whom data regarding iodine status (baseline and during stimulation), dietary habits, thyroid function, ovarian reserve parameters (AFC and AMH), and ART cycle outcomes were collected and analyzed. In the analyzed sample, 63% of patients exhibited iodine deficiency. These percentages remained virtually unchanged during the assessment of urinary iodine concentration during COS. A positive, although weak, but statistically significant correlation emerged between urinary iodine levels and AFC (r = 0.13; p = 0.023) as well as between urinary iodine levels and AMH (r = 0.17; p = 0.002). Stratification of the sample into three iodine status classes (severe deficiency, mild deficiency and normoioduria) revealed a decreasing trend in the percentage of poor ovarian responder (POR) patients as urinary iodine levels increased. No significant associations were found between urinary iodine levels or thyroid function parameters and embryo quality; however, median baseline urinary iodine, TSH, and fT3 levels were found to be higher in patients with better embryo quality. The high prevalence of iodine deficiency found, combined with a marked lack of awareness regarding the iodine prophylaxis campaign, suggests the need for greater attention to iodine status in patients undergoing level II ART pathways. Although diet influences iodine intake, the study highlighted a significantly greater increase in urinary iodine levels in patients taking iodine supplements, thereby supporting the efficacy of supplementation. The significant association with ovarian reserve parameters and urinary iodine levels, which were higher in normo-responder (NOR) patients, supports the hypothesis of a biological role of iodine in ovarian function. Conversely, no statistically significant associations emerged with the main ART outcomes, although mild fluctuations in urinary iodine concentration were observed regarding embryo quality. Iodine thus emerges as a modifiable risk factor and a potential modulator of the reproductive microenvironment, configuring itself as a promising and early target for clinical intervention in ART pathways.
L’interazione tra funzione tiroidea e attività ovarica costituisce un elemento centrale nella fisiopatologia della fertilità femminile. Disfunzioni tiroidee possono alterare meccanismi riproduttivi, quali la follicologenesi, l’ovulazione e l’impianto embrionale. In questo contesto, l’attenzione è rivolta al ruolo dello iodio, micronutriente essenziale per la sintesi degli ormoni tiroidei e determinante per il mantenimento dell’equilibrio endocrino-riproduttivo. Evidenze recenti suggeriscono che lo iodio possa esercitare un’influenza diretta sulla riserva ovarica e, di conseguenza, sugli esiti delle tecniche di PMA, sottolineando l’importanza di una valutazione completa dello stato tiroideo e nutrizionale nella gestione della fertilità. Il presente studio si propone di approfondire il ruolo dello iodio nella funzione riproduttiva femminile all’interno di una popolazione di donne infertili candidate a percorsi di PMA. L’obiettivo è indagare le possibili correlazioni tra lo stato iodico (stimato attraverso campioni di ioduria), la funzionalità tiroidea e la riserva ovarica. Si intende inoltre analizzare tali associazioni nel contesto dinamico della stimolazione ovarica controllata (COS), valutando la relazione con i principali outcomes clinici della PMA. Infine, lo studio mira a contestualizzare lo stato iodico delle pazienti in relazione alle loro abitudini alimentari. Lo studio osservazionale monocentrico è stato condotto presso l’Unità Operativa di PMA dell’Ospedale di Padova. Il campione ha incluso donne con diagnosi di infertilità, per le quali sono stati raccolti e analizzati dati relativi a status iodico (basale e in fase di stimolazione), abitudini alimentari, funzionalità tiroidea, parametri di riserva ovarica ed esiti di PMA. Nel campione analizzato, il 63% delle pazienti ha evidenziato uno stato di iodocarenza. È emersa una correlazione positiva, seppur debole ma statisticamente significativa tra ioduria e AFC (r=0,13; p=0,023) e tra ioduria e AMH (r=0,17; p=0,002). La stratificazione del campione in tre classi di ioduria (deficit severo, deficit lieve e normoioduria) ha mostrato un trend decrescente della percentuale di pazienti poor ovarian responders (POR) all’aumentare dei livelli di ioduria. Non sono state riscontrate associazioni significative tra ioduria o parametri di funzionalità tiroidea e qualità embrionale; tuttavia, i valori mediani di ioduria basale, di TSH e di fT3 sono risultati più elevati nelle pazienti con migliore qualità embrionaria. L’elevata prevalenza di iodocarenza riscontrata, associata a una marcata disinformazione della campagna di iodoprofilassi, suggerisce la necessità di una maggiore attenzione allo stato iodico nelle pazienti che scelgono un percorso di PMA di II livello. Sebbene l’alimentazione influisca sull’apporto iodico, lo studio ha evidenziato un incremento maggiore dei livelli di ioduria nelle pazienti che assumevano integratori iodici, supportando l’efficacia della supplementazione. L’associazione significativa con i parametri di riserva ovarica e i livelli di ioduria, superiori nelle pazienti normo-responders (NOR), avvalorano l’ipotesi di un ruolo biologico dello iodio sulla funzionalità ovarica. Al contrario, non emergono associazioni statisticamente significative con i principali esiti di PMA. Lo iodio emerge quindi come un potenziale modulatore del microambiente riproduttivo, configurandosi come un promettente target d'intervento clinico nei percorsi di PMA.
Lo iodio nella fertilità femminile: relazione tra ioduria, abitudini alimentari e outcomes nei percorsi di PMA.
PUNTEL, FRANCESCA
2025/2026
Abstract
The interaction between thyroid function and ovarian activity constitutes a pivotal element in the pathophysiology of female fertility. Thyroid dysfunctions, including subclinical forms, can impair fundamental reproductive mechanisms such as folliculogenesis, ovulation, and embryo implantation. In this context, growing attention is focused on the role of iodine, an essential micronutrient for thyroid hormone synthesis and a key determinant in maintaining endocrine-reproductive balance. Recent evidence suggests that iodine may exert a direct influence on ovarian reserve and, consequently, on the outcomes of Assisted Reproductive Technology (ART), highlighting the importance of a comprehensive assessment of thyroid and nutritional status in fertility management. This study aims to investigate the role of iodine status in female reproductive function within a population of infertile women undergoing ART pathways. Specifically, the objective is to investigate potential correlations between iodine status (estimated via urinary iodine concentration, UIC), thyroid function, and ovarian reserve. Furthermore, it aims to analyze these associations within the dynamic context of controlled ovarian stimulation (COS), evaluating the relationship between urinary iodine levels and the primary clinical outcomes of ART. Lastly, the study seeks to contextualize patients' iodine status in relation to their dietary habits, in order to explore potential nutritional determinants of iodine intake and their impact on reproductive outcomes. This single-center observational study was conducted at the ART Unit of the University Hospital of Padua. The sample included women diagnosed with infertility, for whom data regarding iodine status (baseline and during stimulation), dietary habits, thyroid function, ovarian reserve parameters (AFC and AMH), and ART cycle outcomes were collected and analyzed. In the analyzed sample, 63% of patients exhibited iodine deficiency. These percentages remained virtually unchanged during the assessment of urinary iodine concentration during COS. A positive, although weak, but statistically significant correlation emerged between urinary iodine levels and AFC (r = 0.13; p = 0.023) as well as between urinary iodine levels and AMH (r = 0.17; p = 0.002). Stratification of the sample into three iodine status classes (severe deficiency, mild deficiency and normoioduria) revealed a decreasing trend in the percentage of poor ovarian responder (POR) patients as urinary iodine levels increased. No significant associations were found between urinary iodine levels or thyroid function parameters and embryo quality; however, median baseline urinary iodine, TSH, and fT3 levels were found to be higher in patients with better embryo quality. The high prevalence of iodine deficiency found, combined with a marked lack of awareness regarding the iodine prophylaxis campaign, suggests the need for greater attention to iodine status in patients undergoing level II ART pathways. Although diet influences iodine intake, the study highlighted a significantly greater increase in urinary iodine levels in patients taking iodine supplements, thereby supporting the efficacy of supplementation. The significant association with ovarian reserve parameters and urinary iodine levels, which were higher in normo-responder (NOR) patients, supports the hypothesis of a biological role of iodine in ovarian function. Conversely, no statistically significant associations emerged with the main ART outcomes, although mild fluctuations in urinary iodine concentration were observed regarding embryo quality. Iodine thus emerges as a modifiable risk factor and a potential modulator of the reproductive microenvironment, configuring itself as a promising and early target for clinical intervention in ART pathways.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/109173