Impact of Vitamin D Deficiency on Menstrual Irregularities and Fertility Outcomes in Women of Childbearing Age

Abstract

Vitamin D is increasingly recognized as a key regulator of reproductive function due to its role in ovarian folliculogenesis, endometrial receptivity, and hormonal balance. Objective: To assess the impact of vitamin D deficiency on menstrual irregularities and fertility outcomes in women of reproductive age. Methodology: This cross-sectional analytical study was conducted at Services Hospital, Lahore, from September 2023 to September 2024. A total of 195 women aged 18–40 years were enrolled using consecutive sampling. Participants with known endocrine disorders or recent vitamin D supplementation were excluded. Demographic and reproductive histories were collected via structured questionnaires. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured using chemiluminescent immunoassay and classified as deficient (<20 ng/mL), insufficient (20–30 ng/mL), or sufficient (>30 ng/mL). Results: The mean age of participants was 28.7 ± 4.6 years, with a mean BMI of 26.4 ± 3.9 kg/m². Vitamin D deficiency was observed in 98 women (50.3%), insufficiency in 57 (29.2%), and sufficiency in 40 (20.5%). Menstrual irregularities were significantly more common in the deficient group (85.7%) compared to the insufficient (49.1%) and sufficient (42.5%) groups (p < 0.001). Among married women (n = 112), infertility was reported in 72.1% of the deficient group versus 27.3% of the sufficient group (p = 0.002). Miscarriage and recurrent miscarriage were also more frequent in vitamin D-deficient women (p < 0.05). Conclusion: Vitamin D deficiency is highly prevalent among women of childbearing age and is strongly associated with menstrual irregularities and poor fertility outcomes. Routine screening and correction of deficiency may represent a low-cost, effective strategy to improve reproductive health and reduce infertility burden.