HERE COMES THE SUN: SERUM VITAMIN D LEVELS AND INTRAUTERINE INSEMINATION SUCCESS IN WOMEN OF ADVANCED MATERNAL AGE

Abstract

Vitamin D is often thought to play an integral role in human reproduction. Previous research has shown vitamin D receptors to be located throughout the endometrium and on the granulosa cells of growing follicles, implicating its necessity in adequate reproductive function. As such, studies show that women deficient in vitamin D have decreased probability of live birth after IVF. Yet, more recent studies have found that the same is not true for women undergoing intrauterine insemination (IUI), as vitamin D levels did not seem to impact pregnancy rates. Thus, we sought to better understand the relationship between vitamin D and reproductive success among infertile women. The purpose of this study was to determine the relationship between serum vitamin D levels and IUI success rates in women of advanced maternal age. All patients over the age of 40 who underwent IUI between January 2017 - August 2019 were included. All patients received a basic fertility work up, including serum vitamin D and AMH levels, as well as ultrasound evaluations. Sufficient serum vitamin D levels were defined > 20 ng/mL. Thus, patients were divided into two groups: patients with vitamin D deficiency (0-19.99 ng/mL) and vitamin D sufficiency (>20 ng/mL) at baseline. Serum HCG levels were taken 12 days post-IUI. Positive pregnancy was defined as a blood HCG >5 (units). Clinical pregnancy rate and miscarriage rates were also noted. T-tests and chi square analysis were used to analyze the data using SPSS (SPSS Inc., Chicago, IL, USA). A total of 167 patients were analyzed. Baseline characteristics between the two groups, including age, BMI, and AMH were insignificant. The average baseline vitamin D level for deficient patients was 15.53 ng/mL while the average for sufficient patients was 35.83 ng/nL. There was a statistically significant difference in pregnancy rates between women over 40 with deficient and sufficient vitamin D levels (p<0.001). Of note, a negative correlation was found between vitamin D and AMH (p<0.05). Although previous research showed that vitamin D levels had no effect on IUI success in women under 40 years of age, here we demonstrated that vitamin D sufficiency in women over 40 years of age may play a role in IUI success. Further research is needed to analyze the costs and benefits of allotting time for women of advanced maternal age to replenish their vitamin D levels if they are pursuing IUI.