Objectives: Spontaneous abortion is the most common pregnancy complications that can had a bad psychological effect on the lives of couples seeking to have a baby. In the early stages Continuation of pregnancy, depends on progesterone production by the corpus luteum. Impaired glucose metabolism during pregnancy is the most important diseases in pregnancy, using oral progesterone to prevent preterm delivery in pregnant women are widely prescribed by gynecologists. We decided to study the effect of oral progesterone (dydrogestron) on incidence of glucose intolerance in pregnant females with threatened abortion. Design & setting & conduct: In this prospective study 50 pregnant women who were tested for blood sugar and had normal blood sugar levels with gestational age less than 14 weeks and complaint threatened abortion, had administration of oral Dydrogesterone 10 mg twice daily to prevent miscarriage and preterm delivery. 50 women who did not use oral dydrogesterone formed the control group. Inclusion criteria: singleton pregnancy, the absence of any systemic disease, age less than 30 years, BMI less than 25, no history of stillbirth, having a family history of diabetes Exclusion criteria: smoking, history of diabetes, gestational diabetes and other systemic diseases, any fetal abnormalities on ultrasound, multiple pregnancy, and previous macrosomia. Interventions: oral administration of dydrogesterone 10 mg twice daily. Outcome: GTT and GCT was checked in14 weeks of gestational age Pregnancy.