Maternal age, obstetric complications, and the outcome of pregnancy.

Data from 44,386 pregnancies were analyzed to determine if advancing maternal age influences frequency or outcome of antenatal disorders. The perinatal mortality rate progressively increased from 25/1000 at age 17 ro 19 years to 69/1000 after age 39. Stillbirths accounted for 92% of this increase. Fourteen percent of the increase was due to congenital malformations and 50% to disorders associated with uteroplacental underperfusion, ie, abruptio placentae, large placental infarcts, and placental growth retardation. Sclerotic lesions in the myometrial arteries are a possible cause of underperfusion because the proportion of arteries with these lesions increased from 11% at age 17 to 19 years to 83% after age 39.