Introduction: Patients with threatened miscarriage associated with adverse pregnancy outcomes because of associated pregnancy and labor
complications. Objectives: To evaluate the effect of threatened miscarriage on early and late pregnancy outcome. Methods: A retrospective case
–controlled study was performed on 89 women with threatened miscarriage (study group) at Maternity and Children Hospital Buraidah, KSA from
January 2010 to December 2010. They were matched for age and parity to 45 cases (control group) attending route antenatal clinic at the same time.
Data recorded included, demographic characteristics and detailed pregnancy outcome and ultrasound finding including gestational age, cardiac
activity and subchorionic hematoma. Results: The overall adverse pregnancy outcome was significantly higher in the studied cases compared to
the control group (p=015).The miscarriage rate was significantly higher in study group compared to the controls group, (16.9%vs 2.2%, p=0000).
Preterm delivery, babies with low birth weight and premature rupture of membranes were significantly higher in the miscarriage group compared
to the controls group, (15.7% vs 2.2%, p=0.001), (15.7% vs 2.2%), p=0.001) and (6.7%) vs 4.45), p=0.016). There were no significant differences in
other pregnancy outcomes. Conclusion: threatened miscarriage is associated with increased incidence of adverse pregnancy outcome. The risk
is specially increased in premature rupture of the membranes, preterm delivery and neonatal birth weight.