Objective To compare late-preterm infants (33–36 weeks) with term infants (≥37 weeks) on incidence of morbidities in the first 3 years of life and healthcare costs during the first 2 years of life and third year of life.

Methods Administrative health records of live infants born between January 1, 1997, and December 31, 2000 with 3 years follow-up data (N=35733) were linked. First, diagnoses of morbidities were compared between late-preterm and term infants using Cox's proportional hazards models. Healthcare costs expressed as mean total costs and cost ratios, accrued following initial hospital discharge after birth, were also examined.

Results The three most common reasons for hospitalisation in late-preterm and term infants were acute bronchitis, otitis media and pneumonia. The most frequent reasons for physician visits included acute upper respiratory infections, otitis media and bronchiolitis. The highest HR were detected for chronic bronchitis 1.64 (1.13–2.39), hearing loss 1.56 (1.14–2.15) and bacterial diseases 1.28 (1.09–1.49). The mean total cost for late-preterm infants during the first 2 years of life was $2568 CAD compared with $1285 CAD for term infants, cost ratio =1.99 (95% CI 1.90 to 2.09). In the third year of life, the cost ratio reduced to 1.46 (95% CI 1.39 to 1.54).

Conclusions Late-preterm infants are at higher risk of specific morbidities compared with term infants. Their mean total costs fall from almost double that of term infants during the first 2 years of life, to just 46% greater in the third year of life.