This a case-control study which was performed during the period from (December 2013) till (June 2014). Researcher had 80 participants presented to the outpatient clinic in Ain Shams University Maternity hospital; they were classified into two groups: (Group A) case group: 40 pregnant females at 6- 13wks presenting with a history of recurrent pregnancy loss (two or more failed clinical pregnancies as documented by ultrasonography or histopathology examination according to the American Society of Reproductive Medicine). (Group B) control group: 40 pregnant females at 6- 13wks with no history of abortion. They were selected according to inclusion and exclusion criteria: