Objective: High risk infants are those who have a history of one or more risk factors in prenatal, perinatal or postnatal period in their developmental period, shown as developmental delay (DD). The incidence of DD in these infants is higher than normal. This study is done in order to determine the incidence of motor developmental delay (MDD) and effective risk factors in developing of it in high risk infants who have been refered to developmental disorders center of SABA.

Materials & Methods: Study is a descriptive (incidence determination) and analytic case – control type (Effective high risk factors determination). The samples include 403 referred infants from health centers and pediatric clinics of Tehran that have the history of one or more risk factors. The infants with MDD defined as cases and infants who had refered to SABA center for other reasons as controls.

Results: The incidence of MDD in high risk infants was 30% that was significantly higher that of normal values. The most effective risk factors were prematurity (25.6), low birth weight (19%), neonatal seizures (7.4%), hyaline membrane disease (6.6%) systemic infections of mothers in pregnancy (5.7%) and severe neonatal hyperbilirubinemia (4.9%) in sequence. 

Conclusion: Regarding to effect of above risk factors in developing of MDD necessary and suitable attempts should be done for prevention of these factors in order to decreasing the incidence of DD. Developmental delayed infants also should be diagnosed early in order to early intervention rehabilitation & therapy in order to achieve a better results.