Effect of serum vitamin D level on endometrial thickness and parameters of follicle growth in infertile women undergoing induction of ovulation.

In this paper, 153 infertile women undergoing induction of ovulation at an academic tertiary care centre were included in a cross-sectional study. Serum Vitamin D level was measured and the rate of clinical pregnancy (defined as a sonographic presence of FHR of an intrauterine gestational sac) and patient and cycle parameters were determined. The results showed that a correlation exists between endometrial thickness as well as the number of antral follicles and replete level of Vitamin D. Interestingly, the median level of these two parameters was of upmost level in the most replete tertile of serum Vitamin D level. There was no correlation between the serum level of Vitamin D and pregnancy rate. Vitamin D status was associated with endometrial thickness and number of antral follicles, but this study did not find a pivotal effect of serum Vitamin D level on pregnancy rate. Impact statement What is already known on this subject? Literature reviews have indicated that a Vitamin D deficiency is directly responsible for a reduced fertility and reproduction capacity. Women with higher level of Vitamin D in serum and follicular fluid are more likely to become pregnant. What do the results of this study add? This study, assessing the effect of serum level of Vitamin D on endometrial thickness and parameters of follicle growth in infertile women undergoing induction of ovulation showed that a correlation exists between endometrial thickness as well as the number of antral follicles and replete level of Vitamin D. It can be concluded that a replete Vitamin D status is associated with a better state of endometrial thickness and a number of antral follicles, but this study did not find a pivotal effect of serum Vitamin D level on the pregnancy rate. What are the implications of these findings for clinical practice and further research? If a relationship would be proved between Vitamin D deficiency and endometrial thickness and parameters of follicle growth it is possible that with prescribing supplemental Vitamin D as a relatively inexpensive and safe way along with the other more complex and costly infertility treatments, achieving the pregnancy would be easier.