Previous studies have suggested that vitamin D deficiency is common in patients with recurrent spontaneous abortion (RSA) and may be associated with immune-inflammatory imbalance and a prothrombotic state. In light of this, this study aims to investigate the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels and inflammatory response as well as prothrombotic state in RSA patients.

A retrospective cohort study was conducted on 220 RSA patients who visited our reproductive medicine center between January 2022 and August 2023. Clinical data were analyzed, and serum levels of 25(OH)D, inflammatory markers (IL-6, TNF-α, IL-10, hsCRP), prothrombotic state indicators [total homocysteine (tHCY), D-dimer], glucolipid metabolism parameters, thyroid function, immune cell subsets and ovarian reserve function were assessed. According to 25(OH)D levels, these RSA patients were stratified into a severe deficiency group (<10 ng/mL, n=14), a deficiency group (10 to <20 ng/mL, n=140), an insufficiency group (20 to <30 ng/mL, n=53), and a sufficiency group (≥30 ng/mL, n=13). The abovementioned indicators were compared among the groups. Mann-Whitney U test was used for comparisons between 2 groups. For comparisons among more than 2 groups, Kruskal-Wallis H test was performed followed by Dunn’s post hoc test. Spearman and partial correlation analyses were applied to evaluate associations between 25(OH)D and related indicators.

Vitamin D deficiency or insufficiency was observed in 94.09% of the cohort. Compared with the patients with 25(OH)D ≥20 ng/mL, those with levels <20 ng/mL had significantly higher tHCY levels [8.35 (7.23 to 9.60) μmol/L vs 7.60 (6.35 to 8.95) μmol/L, P=0.007]. No statistical differences were observed in the intergroup comparisons in glucolipid metabolism, thyroid function, inflammatory markers, immune cell subsets or ovarian reserve function. Spearman correlation analysis showed that serum 25(OH)D levels were negatively correlated with tHCY (r=-0.222, P<0.01), and this association remained significant after adjusting for age and body mass index (r=-0.188, P=0.019). In the patients with 25(OH)D <30 ng/mL, a weak negative correlation was observed between 25(OH)D and IL-6 (r=-0.159, P<0.05), but this difference was not statistically significant after adjustment.

Vitamin D deficiency is quite common in RSA patients. Lower 25(OH)D levels are associated with an altered prothrombotic profile, particularly elevated tHCY, whereas their association with inflammatory markers appears limited. These findings suggest that vitamin D status may be involved in the regulation of thrombotic risk associated with RSA.

To investigate the effect of insulin resistance (IR) in primary infertile couples on pregnancy outcomes in fresh cycle embryo transfer.

A total of 101 primary infertile couples who underwent first IVF-ET/ICSI assisted conception with fresh cycle embryo transfer in our reproductive medical center from October 2022 to October 2023 were retrospectively included. According to whether they had combined IR unilaterally, these couples were divided into female IR group (n=49) and female non-IR group (n=52), and male IR group (n=49) and male non-IR group (n=52). The basic data, ovulation promotion, embryo transfer and pregnancy outcome were compared between the female IR group and non-IR group, and between the male IR group and non-IR group. Logistic regression analysis was applied to determine the effect of IR on pregnancy outcome and laboratory indicators of ovulation promotion.

①The IR female group had significantly higher body weight and BMI, and lower antral follicle count (AFC) when compared with the non-IR female group (P<0.05). ②Female fasting blood glucose was negatively correlated with the number of acquired eggs, number of metaphase Ⅱ (MII) oocytes, number of transferable embryos, and number of high-quality embryos (P<0.05); and both female fasting insulin level and female HOMA-IR were positively correlated with the days and total amount of gonadotropin (GN) (P<0.05). ③Embryo implantation and clinical pregnancy rates were significantly lower in the female IR group than the female non-IR group (P<0.05). ④The male IR group had significantly higher BMI than the male non-IR group (P<0.05). ⑤Embryo implantation rate and clinical pregnancy rate were in declining trend in all following 3 groups of couples (both IR groups, single IR group, and neither IR group). ⑥Female fasting blood glucose level showed a negative effect on number of acquired eggs, number of MII oocytes, number of transferable embryos, and number of high-quality embryos.

IR affects embryo quality in IVF/ICSI cycles in women with primary infertility; IR in couples with primary infertility negatively affects embryo implantation rates and clinical pregnancy rates in IVF/ICSI cycles.