The influence of prolonged pregnancy on infant development at one and two years of age: a prospective controlled study.

Isolated reports of developmental disturbances following prolonged pregnancy led us to compare, prospectively, at 1 and 2 years of age, infants born after normal term gestations with those born after prolonged pregnancies (exceeding 294 days). The infants were subgrouped according to their physical condition at birth, that is, normal or dysmature (mild or advanced dysmaturity). Infant assessments included: (1) height and weight, (2) hospitalizations, and (3) mental development by the Griffiths Mental Development Scales. Follow-up testing was obtained on 130 term control infants and 89 infants of prolonged pregnancies at 1 year of age and 111 term control infants and 76 infants of prolonged pregnancies at 2 years of age. At 1 and 2 years the general intelligence quotient, physical milestones, and intercurrent illnesses for normal infants and those of prolonged pregnancies were not significantly different.