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Outcome of infants born preterm, with special emphasis on extremely low birthweight infants
1Maternal and Perinatal Center, Tokyo Women's Medical College, Japan.
Insights
Outcomes for extremely low birthweight (ELBW) infants improved with intensive care, reducing mortality. However, neurological sequelae and poor school performance remain challenges for these vulnerable infants.
Area of Science:
- Neonatal care
- Pediatric neurology
- Perinatal medicine
Background:
- Extremely low birthweight (ELBW) infants face significant mortality and morbidity risks.
- Advances in intensive care have improved survival rates for ELBW infants.
- Long-term neurodevelopmental outcomes and growth patterns require continued monitoring.
Purpose of the Study:
- To review the outcomes of extremely low birthweight (ELBW) infants based on published literature and Japanese data.
- To analyze trends in mortality, neurological sequelae, and long-term development.
- To discuss the viability limits of ELBW infants in the context of evolving medical care.
Main Methods:
- Literature review of published articles on ELBW infant outcomes.
- Analysis of up-to-date data from Japan, including mortality rates and incidence of neurological sequelae.
- Long-term follow-up studies of ELBW children to school age.
Main Results:
- Mortality rates for ELBW infants declined significantly post-1970s intensive care introduction, but major neurological sequelae incidence remained stable around 20%.
- Neurological sequelae incidence did not correlate with decreased birthweight, though mortality increased.
- Long-term follow-up revealed poor school performance despite normal IQ and absence of major neurological sequelae; physical growth catch-up occurred by 8-9 years.
Conclusions:
- Intensive care has dramatically reduced ELBW infant mortality, but neurological sequelae and academic challenges persist.
- The viability limit for ELBW infants in Japan was revised to 22 weeks gestation due to medical advancements.
- Further research and support are needed to address the long-term neurodevelopmental and educational needs of ELBW survivors.
Abstract:
The outcome of extremely low birthweight (ELBW) infants has been reviewed from published articles and up-to-date data from Japan. The mortality rate of these infants declined significantly from over 90% to below 50% after the introduction of intensive care in the 1970s, but the incidence of major neurological sequelae remained steady at around 20%. Similarly, the incidence of major neurological sequelae did not increase along with the decrement of birthweight, although the mortality rate increased significantly. Long-term follow-up of ELBW children until school age has revealed poor school performance in spite of the absence of major neurological sequelae and the attainment of average intelligence quotient scores. Physical growth is retarded initially but generally catches up by the age of 8-9 years. In Japan, the neonatal mortality rate of ELBW infants declined from 56% in 1981 to 25% in 1989 with an increased birth rate of ELBW infants. In ELBW infants cared for at Tokyo Women's Medical College during 1984-90, the survival rate was 112 out of 134 (84%) and the incidence of major neurological sequelae was 15 out of 87 (17%) at 1-8 years old. The viability limit of ELBW infants has been discussed based on recent data. As a result of the rapid progress of medical care of ELBW infants, their viability limit as defined in the Eugenic Protection Law in Japan was amended from 24 completed weeks of gestation to 22 completed weeks in 1991.