Introduction: Preterm birth (PTB, <37 weeks gestation), is the leading cause of infant death and long-term morbidity. PTB is categorized by the World Health Organization as follows: early(<32 weeks), moderate(32-33 weeks), and late(34-36 weeks), as well as through phenotypes (spontaneous/iatrogenic). Late-preterm and early-term infants have fewer immediate health issues, yet emerging research indicates increased risk of poorer long-term social and health outcomes, including developmental delay. Despite this, ongoing developmental follow-up is not routinely offered.
Objectives: 1)Describe the distribution of gestational-age (GA) categorizations, and phenotypes of PTB, and 2)Compare category specific prevalence of developmental delays in children at three years of age.
Methods: Data: This study used data from All Our Families Study, a prospective pregnancy cohort of 3200 women from Calgary with information on birth, child health and development outcomes (Ages & Stages Questionnaire domains: communication, gross-motor, fine-motor, problem-solving, and personal-social skills). Women completed questionnaires twice during pregnancy, and at four months, and 1, 2, and 3 years postpartum.
Analysis: 1)Prevalence for phenotypes and categories of GA (including full-term: 39-40 weeks, late-term: 41-42 weeks). 2) Cross-tabulations of developmental delay prevalence against GA categorizations were
compared using chi-square and 95% CIs.
Results: GA specific prevalence were as follows: early-preterm 0.76%(95%CI:0.42-0.12%), moderate-preterm 0.71(95%CI:0.38-0.12%), late-preterm 4.54%(95%CI:3.67-5.56%), early-term 24.47%(95%CI:22.59-26.43%), full-term 54.69%(95%CI:52.47-56.90%), and late-term 13.98%95%CI:12.48-15.58%). The prevalence of fine-motor developmental delay in the combined moderate/late-preterm births 25.81%(95%CI: 17.29-35.92%) was significantly higher (p<0.01) from full-term 13.89%(95%CI:11.8-16.18%), and the prevalence of delay within personal-social domain for moderate/late-preterm 21.28(95%CI:13.51-30.93%) is significantly higher (p=0.003) than full-term 9.51%(95%CI:7.76-11.5%). The prevalence of developmental delay among PTB categories does not vary by preterm phenotype.
Conclusion: The results of this study indicate developmental delay occurring at/before three-years is correlated with GA at birth. Developmental delay may become more pronounced through the preschool years, and research on the trajectories of longer-term outcomes is necessary.
Jessica Walsh– Trainee, university of calgary
Suzanne Tough– Professor, Department of Paediatrics, University of Calgary, Calgary, AB
Muci Wu– Analyst, University of Calgary
Sheila McDonald– Co-Investigator, Alberta Health Services, University of Calgary
Nikki Stephenson– University of Calgary