Changing Characteristics of Neonatal Follow-up Studies

Objectives

After completing this article, readers should be able to:

1. Describe changes over time in the characteristics of study subjects in neonatal follow-up studies.

2. Describe changes over time in the outcome assessments of neonatal follow-up studies.

3. Delineate four broad research themes of neonatal follow-up studies.

4. Summarize the evolution of studies of the prevalence of disability and contributing causes of developmental impairments in preterm infants.

5. Summarize the evolution of studies of severely ill term and near-term infants.

Introduction

Within a few years of the opening of the first preterm infant nursery in the United States in 1922, reports appeared describing the long-term outcomes of treated infants. Early studies of health and developmental outcome described the frequency of impairments for specific groups of high-risk neonates. More recently, neonatal follow-up studies have been used to evaluate the effectiveness of therapeutic interventions and to test specific hypotheses about the etiology of an impairment.

The outcome of interest in neonatal follow-up studies is the health or development, beyond the first months of life, of high-risk neonates. In observational follow-up studies, risk factors of interest have included biologic (eg, perinatally acquired brain damage), environmental (eg, maternal depression), and “established” risk factors (eg, cytomegalovirus infection, genetic syndromes).

Table 1⇓ summarizes changes in research methods in follow-up studies during the 20th century Based on epidemiologic principles, Kiely and Paneth offered the following suggestions for improving neonatal follow-up studies: 1) use of population-based rather than hospital-based samples for prevalence studies; 2) inclusion of appropriate controls; 3) assessment of confounding due to social class; and 4) minimizing lost-to-follow-up rates. In addition, they commented on issues specific to neonatal follow-up, including: 1) continued follow-up of subjects to school age; 2) reporting of mortality rates as well as morbidity; 3) reporting of birthweight-specific data; and 4) more detailed reporting of the co-occurrence of …