Background and Objective: Due to the effect of garlic on immune system and a relationship between immune responses and pregnancy outcome, we designed this study to evaluate the effect of immunomodulator fraction of garlic (R10) on main parameters in pregnancy period. Materials and Methods: One week after mating of 30 female BALB/c mice, they were divided into four groups: one group received R10 fraction for one week, one group received R10 fraction for two weeks and their corresponding control groups. Intraperitoneal injection of 0.2 mg/kg of the fraction continued until 18th days of pregnancy. During this time, blood pressure was measured and their urine for protein and creatinnine assay and serum for uric acid assay were collected. Results: Injection of 0.2 mg/kg of R10 fraction for two weeks significantly increased systolic blood pressure, declined urine protein and protein to craetinene ratio in non-pregnant mice. No significant difference was observed regarding urine creatinine between the groups. In both groups (i.e. pregnant and non-pregnant), serum level of uric acid increased as compared to control group.  Conclusion: Garlic isolated R10 fraction which was used at a higher dose in this study compared to its immunostimulatory dose increased blood pressure and uric acid. Since this may cause preeclampsia, it is suggested to have precaution for use of high dose garlic and R10 fraction in pregnancy period and more study are warranted on pregnancy in human and animal models.