Prevalence of Vitamin D Levels in the Recurrent Pregnancy Loss Population

Vitamin D obtained from exposure to sun, food, and supplements. According to the Institute of Medicine, Food and Nutrition Board calcidiol reference serum ranges are: deficient <30nmol/L, inadequate 30-50nmol/L, adequate >=50nmol/L. Many genes encoding proteins that regulate cell proliferation, differentiation, and apoptosis are modulated in part by vitamin D (VD). Serum concentration of 25(OH)D is the best indicator of vitamin D status. It functions as a biomarker of exposure, but it is not clear to what extent levels serve as a biomarker of effect.

Due to the presumed effect on the endometrial immune milieu, we have investigated its levels in a population of women with RPL. There is limited information about the prevalence of vitamin D deficiency in the recurrent miscarriage population. As the hypothesis is that vitamin D can be a marker of endometrial dysfunction, the levels may be different in women with a history of ongoing pregnancies. Before including vitamin D as a standard in the recurrent miscarriage screening prevalence needs to be established.

Material and Methods: Women referred for RPL investigations were all offered screening for vitamin D levels. They were thereafter seen in clinic, where a detailed history was obtained.

Results: From May 2015 until June 2016, 173 women were referred. VD levels were obtained in 116 women, mean BMI 26 kg/m2, mean age 35 years, 51.7% primary RPL. Mean VD levels were 55.5±23.1 nmol/L. In the study population, 73 (63%) women had adequate levels, 27 (23%) inadequate levels and 16 (14%) had deficient levels. No significant difference in VD levels could be found between primary versus secondary RPL.

Discussion: In our RPL population, 37% of women had low VD levels, however this did not correlate with pregnancy outcomes (or other analyzed variables). This might be related to the short follow up period and the small number of pregnancies achieved so far.