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Extremely low birth weight is linked to risk of chronic illness

BMJ 2005; 331 doi: (Published 21 July 2005) Cite this as: BMJ 2005;331:180
  1. Susan Mayor
  1. London

    Babies with an extremely low birth weight (<1000 g) have a higher risk of developing chronic health conditions, a new study shows. And as well as a having a higher risk of illnesses such as asthma, these babies are more likely than babies of normal birth weight to have functional and educational limitations, the follow-up study shows (JAMA 2005;294: 318-25).

    The US study looked at health outcomes at the age of eight years in a group of children who had an extremely low birth weight. The children were 219 survivors of the cohort of 344 extremely low birthweight children admitted to the neonatal intensive care unit at one hospital, Rainbow Babies and Children's Hospital, in Cleveland, Ohio, between 1992 and 1995. They were compared with 176 normal birthweight controls of similar sociodemographic status.

    Embedded Image

    Extremely low birthweight children, like the baby pictured above, are more than three times as likely as normal birthweight children to have chronic conditions, including functional limitations

    Credit: FOTEX/REX

    The researchers found that extremely low birthweight children were more than three times as likely as normal birthweight children to have chronic conditions, including functional limitations (64% v 20%; odds ratio 8.1 (95% confidence interval 5.0 to 13.1), after data were adjusted for sociodemographic status and sex.

    They were twice as likely to need medical interventions or services to compensate for limited function (48% v 23%; odds ratio 3.0 (1.9 to 4.7)) and to need more services than those routinely required by children (65% v 27%; odds ratio 5.4 (3.4 to 8.5)). These differences remained significant even when the 36 extremely low birthweight children with neurosensory impairments were excluded from the analysis.

    Differences for specific diagnoses and disabilities included cerebral palsy (14% v 0%; P<0.001), asthma (21% v 9%; odds ratio 3.0 (1.6 to 5.6)), and vision of less than 20/200 (10% v 3%; odds ratio 3.1 (1.2 to 7.8)). Educational deficits included IQ <85 (38% v 14%; odds ratio 4.5 (2.7 to 7.7)) and limited academic skills (37% v 15%; odds ratio 4.2 (2.5 to 7.3)). Poor motor skills (47% v 10%; odds ratio 7.8 (4.5 to 13.6)) and poor adaptive functioning (69% v 34%; odds ratio 6.5 (4.0 to 10.6)) were also common among the low birthweight group.

    Advances in perinatal care in the 1990s—including surfactant therapy and more use of antenatal steroids—have resulted in dramatic increases in the survival of extremely low birthweight infants, according to background information in the article. However, little has previously been known about how these children function at school age.

    Maureen Hack, professor of paediatrics and director of high risk follow up at Rainbow Babies and Children's Hospital and lead investigator of the study, said: “Our results reveal that extremely low birthweight children have very high rates of chronic conditions compared with children born at normal weight. These conditions include asthma, cerebral palsy, and visual disability, as well as poorer cognitive ability, academic achievement, motor skills, and social adaptive functioning.”

    Professor Hack added: “The clinical implications are that the children need comprehensive follow-up and anticipatory guidance and care. Proactive planning for their long term health and educational care needs is essential to optimally treat and possibly improve outcomes through preventative and early intervention services.”

    She pointed out that although extremely low birthweight children constitute less than 1% of babies and thus the societal impact is not enormous, the effect on families is enormous.

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