Adjuvant vitamin D therapy may improve pregnancy outcomes and immune regulation in patients with recurrent miscarriage, a new study found. 

In the study, published in the Journal of Obstetrics and Gynaecology Research, investigators revealed that vitamin D therapy increased the proportion of regulatory T cells (Tregs), improved metabolic and inflammatory markers, and led to higher pregnancy success rates.

The investigators randomly assigned 104 patients with recurrent miscarriage (RM) to a vitamin D therapy group (n = 52) or a control group (n = 52). Both groups received standard care, which included aspirin therapy; however, the patients in the vitamin D group also received vitamin D supplementation.

This clinical research included patients admitted between March 2022 and February 2023. The investigators assessed key outcomes, including Treg proportions, metabolic markers, immune-inflammatory markers, and pregnancy outcomes.

After treatment, the patients in the vitamin D group demonstrated several significant improvements:

• Higher Treg Levels: Patients in the vitamin D group had a significantly higher proportion of Tregs in their peripheral blood compared with those in the control group (P < .05), which is crucial for immune tolerance during pregnancy.
• Improved Metabolic Markers: Triglycerides, fasting blood glucose, fasting insulin, and leptin levels were lower in the vitamin D group, while adiponectin levels increased (P < .05).
• Reduced Inflammatory Markers: Levels of interleukin-17, gamma interferon, tumor necrosis factor–alpha, and C-reactive protein were lower in the vitamin D group (P < .05), indicating a reduction in immune inflammation.
• Enhanced Hormonal Profiles: Progesterone, luteinizing hormone, and 25-hydroxy vitamin D levels were elevated in the vitamin D group (P < 0.05), contributing to better reproductive outcomes.
• Better Pregnancy Outcomes: The vitamin D group showed a significantly higher pregnancy success rate and a lower preterm birth rate compared with the control group (P < .05).

"Adjuvant treatment with Vitamin D can increase the proportion of regulatory T cells in peripheral blood of [patients] with recurrent abortion, regulate metabolic disorder, alleviate immune inflammation, and improve pregnancy outcome," underscored study author Shaoyun Ling, of the Department of Reproductive Medicine at the Shenzhen Longgang Central Hospital in Shenzhen, China.

The findings suggested that vitamin D could be an effective adjunctive therapy among patients with recurrent miscarriage. By modulating immune responses, reducing inflammation, and improving metabolic parameters, vitamin D supplementation offers a multifaceted approach to addressing the underlying factors contributing to recurrent pregnancy loss.

While the study demonstrated a favorable safety profile for vitamin D therapy, the investigators emphasized the need for personalized dosing to avoid potential adverse effects related to hypervitaminosis D.

Furthermore, the study underscored the potential of vitamin D supplementation as a low-cost, accessible intervention for improving pregnancy outcomes in patients with recurrent miscarriage. Further research is needed to explore the long-term effects and optimal dosing strategies for this patient population.

The author declared no competing interests.