Background/Objectives: Vitamin D deficiency is common in women with polycystic ovary
syndrome (PCOS) and may be associated with metabolic and endocrine disorders as well
as ovulatory dysfunction. Vitamin D supplementation may improve ovarian dysfunction
and follicular development by effecting gene expression. The aim of the present study
was to investigate the effects of vitamin D supplementation in women with PCOS through
a prospective, randomized, two-phase, parallel design, placebo-controlled trial. Methods:
We assessed the impact on ovarian morphology, cycle length, and ovulatory dysfunction.
Transvaginal ultrasonography (TVUS) examinations and clinical laboratory assessments
were conducted at the baseline, and again after 12 and 24 weeks. The participants
received vitamin D (30,000 IU/week) or a placebo (without concurrent metformin use)
for 12 weeks, supplemented with calcium, followed by an additional 12 weeks of vitamin
D treatment. Results: The treatment resulted in improvements in ovarian morphology
and regularity of menstrual cycles in more than half of the patients. Additionally,
vitamin D3 was associated with a significant increase in the ovulation rate. A statistically
significant reduction in mean testosterone levels was observed in the subgroup of
patients with an LH/FSH ratio greater than 2. Conclusions: Our results suggest that
vitamin D3 treatment could function as either a standalone or an adjunctive therapy
in the management of PCOS.
