The effects on offspring of premature parturition.

The time of parturition defines the length of the intrauterine period of fetal life, a requisite to achieve adequate adaptation to the external environment. Immaturity, a condition whose severity is inversely related to the length of pregnancy, is the main determinant of the increased morbidity and mortality associated with preterm birth. Despite great advances in medical technology and expertise, mainly after the introduction of the neonatal intensive care units, only one- to two-thirds of infants from the subsets with lower birthweight/gestational age reach survival at discharge. Distinct major neurological and sensorial sequelae, including cerebral palsy, retinopathy of prematurity, and hearing loss, as well as reduced neuropsychological abilities, leading to deficient academic achievement and deterioration of several aspects of health status, are still highly prevalent among the most immature children. Interestingly, decreasing mortality rates, which are not followed by detectable increases of disability, are being observed in recent years. Future advances may be expected from clinical and basic research on uterine contractility and cervical softening. Also, changes in reproductive technology procedures, a main factor in the incidence of multiple pregnancies, and a more refined approach to obstetric care, compose some of the clinical interventions which may reduce the problem.