Effect of Vitamin D on Outcome of Assisted Reproductive Technology(ART)

Vitamin D plays an important role in reproduction, while there is high prevalence of vitamin D deficiency. Serum 25(OH)D was categorized according to clinically accepted ranges for vitamin D deficiency (<20 ng/mL), insufficiency (20-30 ng/mL), and replete (>30 ng/mL).

This is a retrospective cohort study of about 2000 infertile couples who undergo their first IVF/ICSI and IUI cycle at Reproductive Medicine Center of Peking University Third Hospital. Patients will be excluded if they refuse to be recruited. Serum samples are collected the day when patients first time to Reproductive Medicine Center and were stored at -20℃ until assayed. Life style of patients is collected by questionair. Vitamin D status is measured by assessing circulating levels of 25(OH)D in frozen, never previously thawed serum samples using radioimmunoassay.

The investigators will comapere the ART outcomes in different groups according to serum 25(OH)D status.

In female, the primary outcome is clinical pregnancy rates defined as the presence of an intrauterinesac with an embryonic pole demonstrating cardiacactivity at 7 weeks of gestation. Secondary outcomes are quality of embryo, positive hCG rates and live birth rates.

In male, the primary outcome is semen quality, such as semen volume, sperm concentration, sperm motility, morphologically normal percent and progressive motile spermatozoa percent. Secondary outcomes are clinical pregnancy rates and live birth rates.