Young Adult Attainments of Preterm Infants

The introduction of methods of neonatal intensive care in the 1960s and 1970s led to significant improvements in the survival and neurodevelopmental outcomes of preterm infants. By the late 1970s, 65% of infants born with very low birth weight (VLBW, <1500 g) and 40% of those of extremely low birth weight (ELBW, <1000 g) survived,¹ of whom 70% to 90% were reported to be without serious impairment during early childhood.¹ However, additional problems became evident during the school age and adolescent years. When compared with term-born children, preterm children demonstrated poorer cognitive function and academic performance; more behavioral problems, mainly hyperactivity and attentional weaknesses but also shy and withdrawn behavior; problems with social skills; and anxiety and depression.² Chronic health problems were also more prevalent and included those problems associated with cerebral palsy, asthma, and visual and hearing impairments. These developmental, behavioral, and health problems led to concern as to how the children would function as they approached adulthood.

The initial survivors of neonatal intensive care reached young adulthood in the mid-1990s. The first reports pertained to VLBW populations.^{3 - 6} Studies from Cleveland, United States,³ Liverpool, England,⁴ and Sweden⁶ revealed inferior educational outcomes with fewer VLBW children than control children graduating from high school and fewer involved in post−high school study at age 20 years. The lesser educational involvement was observed even among VLBW children without neurosensory impairments. However, it was reassuring that the VLBW children reported less risk-taking behaviors and that those VLBW children not involved in educational endeavors were employed at rates similar to control children.

Because birth weight is a major prognostic determinant of long-term outcome, ELBW infants would have been expected to have poorer outcomes in young adulthood than those outcomes reported for VLBW infants.² The results reported by Saigal et al⁷ in this issue of JAMA on the outcomes of a Canadian cohort of ELBW young adults born between 1977 and 1982 thus provide surprising and to a certain extent reassuring information. The young adults, of whom 27% had neurosensory impairments including cerebral palsy, blindness, and deafness, reported no differences in the rates of high school graduation, current educational achievement, or enrollment in college at age 23 years when compared with normal birth-weight controls. Furthermore, there were no differences in the rates of permanent employment, independent living, or marital/cohabitating relationships.

How can these excellent outcomes be explained? The major differences when compared with the Cleveland study are the socioeconomic, societal, and family advantages experienced by the Canadian ELBW young adults. The majority were white and were from 2-parent families, and only 23% were in the lowest social classes. They also had the benefits of a national health care system. In contrast, 55% of the Cleveland VLBW young adults were black and were mainly from poor urban areas, and 41% of their mothers were unmarried. Their health care varied depending on type of health insurance. In both Canada and the United States, support provided for persons with disabilities includes help in school and varying degrees of home and workplace accommodations. The extent to which these are equally applied in the 2 countries is not known. It is also unclear whether the requirements for high school completion in Canada differ for disabled vs nondisabled children compared with various state policies in the United States. Furthermore, the type of financial and practical assistance that the ELBW young adults might have obtained from their families and social services to allow them to live independently have not been described.

According to the recent World Health Organization Classification of Functioning, Disability, and Health,⁸ a person's functioning and disability is conceived as a dynamic interaction between health conditions and contextual factors, which include both personal and environmental factors. Environmental factors that interact with functioning and disability include the facilitating or hindering effect of features of the physical, social, and attitudinal world.⁸ The fact that the Canadian ELBW young adults functioned as well as they did seems mainly due to contextual factors, including their optimal home and family situations and other environmental factors in Canadian society. Some degree of plasticity or improvement in function may also have occurred during adolescence, as suggested by Saigal et al.⁷

However, even the most optimal societal and environmental benefits cannot “fix” the enormous biological risk associated with ELBW. In subanalyses, Saigal et al found that ELBW young adults who graduated from high school, even those without neurosensory impairments, were significantly less likely to complete the requirements for university entrance and fewer were enrolled in or had completed their university education at age 23 years. Furthermore, more ELBW young adults than controls were neither occupied in study nor work, mainly due to chronic illness or permanent disability. Male ELBW young adults had poorer educational outcomes, a finding noted by other studies,³ and they worked in unskilled/semi-skilled jobs rather than management, although this latter finding was not significant.

The extent to which the outcomes of ELBW children who survived during the initial years of neonatal intensive care in the late 1970s and early 1980s can be used to counsel families of current ELBW births is questionable. Technological and therapeutic advances in neonatal intensive care that have accrued over the last 20 years have doubled the rate of survival to 70% to 80%.⁹ Although some neonatal complications are not yet preventable, new therapies may ameliorate outcomes. For example, 19 of the 40 ELBW young adults who had neurosensory impairments had unilateral or bilateral blindness, presumably due to retinopathy of prematurity. Laser therapy may now prevent such blindness.¹⁰ Because a birth-weight cutoff rather than gestational age was used as a criterion for population study selection, most ELBW infants who previously survived were relatively mature but undergrown for their gestational age. Current ELBW study populations include more surviving infants of 24 to 26 weeks' gestation who because of their greater immaturity at birth may have poorer outcomes.⁹

Although a remarkable number of young adult ELBW survivors do very well and are capable of living normal adult lives, there is no place for complacency. The goal of neonatal intensive care is to provide survival without impairment. Biological risk factors prevalent among ELBW infants that result in adult disabilities include mainly brain and pulmonary injury due to periventricular hemorrhage, periventricular leukomalacia, and chronic lung disease. Long-term outcomes of ELBW children can potentially be improved by research to prevent or treat these complications of prematurity and by uniformly implementing postdischarge health and psychosocial family interventions and monitoring. These services are especially relevant for children born into poverty. In a discussion of resilience and “overcoming the odds,” Werner and Smith noted that as the number of biological and psychosocial social risk factors increase, more protective factors are needed to counterbalance the negative aspects in the lives of vulnerable children and to ensure positive developmental outcomes.¹¹ Such principles need to be applied to all ELBW survivors of neonatal intensive care.

Longer-term studies are also needed to evaluate the ultimate educational and occupational achievement of Canadian and other ELBW and VLBW cohorts as they enter mature adulthood in their late 20s, and to assess their independence and adult social relationships. Studies of late adolescents and young adults have reported poorer physical abilities, higher mean blood pressure, poorer respiratory function, and more anxiety and depression for VLBW and ELBW young adults compared with controls.¹² 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.¹³