Babies who were born with an extremely low birth weight (ELBW) are more likely to be disadvantaged in employment, income, self-esteem and marriage by the time they reach their 30s, according to a new study from McMaster University.

The study, published Monday in the scientific journal JAMA Pediatrics, is a longitudinal study that followed a group of ELBW survivors who were born between 1977 and 1982. ELBW babies are infants that are born weighing less than 1,000 grams. Most ELBW babies are also the youngest of premature newborns, typically born at 27 weeks gestation or younger.

Researchers compared 100 ELBW survivors who were born weighing less than 1,000 grams (2.2 lbs) to 89 normal birth weight babies (NBW), who were born weighing more than 2,500 grams (5.5 lbs) and more than 38 weeks gestation.

The participants, now between the ages of 29 and 36, were asked a range of questions concerning their medical, social and psychiatric outcomes.

The study found that compared to the NBW participants, the ELBW participants are:

  • less likely to be employed (80 per cent compared to 92 per cent)
  • less likely to have a full-time job (62 per cent versus 77 per cent);
  • have an average of $20,000 less in personal income;
  • more likely to be single (51 per cent versus 35 per cent);
  • more likely to have never had sexual intercourse (21 per cent versus 2 per cent);
  • less likely to have children (20 per cent versus 33 per cent).

One in five ELBW survivors have a neurosensory impairment, including blindness and cerebral palsy, the study found. When these specific survivors were taken out of the results, the differences in employment, marital status and children are no longer significant.

However, even when excluding these specific survivors, the study found significant differences in personal income, lower self-esteem, alcohol abuse, learning disabilities, incidence of sexual intercourse, mental illness, vision problems, and chronic illnesses between the ELBW group and the NBW group.

On a positive note, the results showed that by the time they reached their early 30s, the ELBW group had the same levels of education, family and partner relationships as the NBW group. As well, they report fewer risky behaviours compared to the NBW group, the study found.

Dr. Saroj Saigal, principal author of the study and professor of pediatrics at McMaster University, has been following the study participants for more than a decade. She said the latest results were not unexpected.

"We didn’t see any major differences between the ELBWs and NBWs then, but they were still very young and just transitioning into adulthood," she said in a statement.

"But now, they are older and are facing a competitive labour market where jobs are scarce. Also, the high proportion with neurosensory impairments accounted for many of the differences between the groups."

Saigal said a significant proportion of the ELBW adults are employed, living independently, and contributing to society. She plans to continue to track their progress.

"It is difficult to predict what the future will hold for these ELBW adults as they reach middle age," she said. "We also need similar studies on newer ELBW survivors to obtain a better understanding of the most pressing issues and to develop effective intervention strategies."

Saigal said this is the first longitudinal study that she's aware of that's followed ELBW infants into their fourth decade of life.

"We've learned a lot since then, and as a result of better nutrition and technological advances, survival of ELBW infants has now nearly doubled."