Beating the Odds of Low Birth Weight

Study: Low-Birth-Weight Babies May Grow Up to Defy Expectations

Reviewed by Louise Chang, MD on February 07, 2006

Feb. 7, 2006 -- Being born with a low birth weight carries many health hazards, but those problems aren't always the end of the story.

Just ask Saroj Saigal, MD, FRCPC, of Canada's McMaster University. Saigal and colleagues followed 149 babies born at extremely low birth weights into adulthood.

"Our study results indicate that a significant majority of extremely low-birth-weight infants have overcome their earlier difficulties to become functional young adults," the researchers write in The Journal of the American Medical Association.

When those babies were in their early 20s, they had graduated high school, gotten a first job, married, and had babies at similar rates as their peers who were born at a normal weight, the study shows.

Tiny at Birth, Triumphant Later

Saigal's study included babies born in the late 1970s and early 1980s who weighed about 1 or 2 pounds at birth. The children were followed from age 8.

In their early to mid-20s, participants did face-to-face interviews with Saigal's team. For comparison, the researchers also interviewed 145 young adults who had been born with normal birth weights. All of the young adults had similar backgrounds.

More than a quarter of people in the low-birth-weight group had significant challenges, such as autism, cerebral palsy, blindness in one or both eyes, and impaired mental abilities.

Still, the two groups kept pace in reaching these milestones:

  • Graduating from high school
  • Getting a first job
  • Living independently from parents
  • Marrying
  • Becoming parents

Participants were still rather young, so few in either group had wed or had babies.

Normal Birth Weight vs. Low Birth Weight

The two groups weren't totally identical in their life paths.

The low-birth-weight group had completed fewer total years of education. That finding was largely due to the academic performance of men in that group, the study shows.

A small group of those with disabilities (less than 4%) required supervised employment in sheltered workshops and were living in group homes.

Still, a "substantial proportion" of disabled adults who had been born at extremely low birth weight "managed to complete high school, were enrolled in university education, lived independently, and were employed," the researchers write.

Surprising Results

The researchers hadn't expected the largely positive results. They had predicted that the low-birth-weight group would lag behind their peers across the board.

"However, contrary to our hypotheses and much of the literature, we have shown that a significant majority of our extremely low-birth-weight participants have made a fairly successful transition from adolescence to adulthood," write Saigal and colleagues.

The researchers can't explain the findings. They don't know if the same is true of today's low-birth-weight babies or those from other circumstances. Most participants were white and came from "relatively advantaged backgrounds," Saigal's team writes.

Access to Canada's national health care program may also have helped, notes a journal editorial.

Poorer physical abilities, higher average blood pressure, poorer respiratory function, and more anxiety and depression have been shown to be more common in adults born at very or extremely low birth weight, the editorial states.

"These and other aspects of health and disease will also need to be followed as these initial survivors of neonatal intensive care continue to age," write the editorialists. They included Maureen Hack, MB, ChB. She works in the pediatrics department of Rainbow Babies and Children's Hospital in Cleveland.

Show Sources

SOURCES: Saigal, S. The Journal of the American Medical Association, Feb. 8, 2006; vol 295: pp 667-675. Hack, M. The Journal of the American Medical Association, Feb. 8, 2006; vol 295: pp 695-696. News release, JAMA/Archives.
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