Endometriosis is a prevalent disease in reproductive aged women causing disabling pain (dyspareunia, dysmenorrhea, pelvic pain) and infertility, many factors have been assessed to find its etiology, but its etiology remains unclear. The serum level of vitamin D is one of the factors that is suspected to be effective in diagnosis or treatment of endometriosis.

The aim of this study was to determine if there is any significant difference between serum levels of vitamin D of women with and without endometriosis. The answer to this question may help the diagnosis or treatment of endometriosis.

In this cross-sectional analytic study on 145 women (aged 16 - 40 years old) who underwent laparoscopy, we took venous blood samples for serum levels of vitamin D before laparoscopy and then divided the samples into two groups based on findings of laparoscopy with endometriosis and without endometriosis. The data was analyzed to compare serum levels of vitamin D in two groups.

After laparoscopy, we had 40 cases of endometriosis and 105 cases without endometriosis. Mean serum level of vitamin D was 19.38 ± 1.65 ng/mL in endometriosis group and 19.96 ± 1.13 ng/mL in the non-endometriosis group with no significant difference (P = 0.68). In 83.4% of samples serum level of vitamin D was less than 30 ng/mL.

To find a more precise data about the role of vitamin D in pathogenesis and treatment of endometriosis, clinical trials are needed to find if the prescription of vitamin D is effective in treatment of endometriosis.