Background: Approximately 12.5 million infants worldwide are born moderate to late preterm (MLPT) at 32-36 weeks’ gestation each year. While at risk for brain lesions and developmental problems, MLPT infants unlike very preterm infants ( < 32 weeks) mostly do not qualify for neurological surveillance, resulting in often late diagnosis of problems. Also, clinical care varies widely across neonatal centers. A better understanding of population characteristics and short- and long-term outcomes may enable advances in care and outcomes of MLPT infants. Objective: To study the occurrence of neonatal morbidity and brain lesions in MLPT infants, and comparison between two MLPT cohorts across continents. Design/Methods: As part of the Brain Imaging in Moderate-late Preterm infants (BIMP) study, brain MRI around term-equivalent age was performed in 121 Canadian and 127 Dutch MLPT infants. For all infants, perinatal and neonatal data, such as mode of delivery, sex, small for gestational age (GA), need for respiratory support, sepsis, feeding problems and age at discharge, were collected. Conventional brain MR images (T1, T2, susceptibility) were assessed by three experts for common preterm brain lesion types, including hemorrhages (intraventricular [IVH], cerebellar [CBH], punctate), white matter injury, cystic lesions, infarction and signs of atrophy (irregular ventricles, wide extracerebral spaces). Neonatal morbidity and brain lesions were calculated for the infants combined and compared between the Canadian and Dutch cohort using appropriate statistical tests. Results: The infants (61% male) had a mean GA of 34.4 weeks and birthweight of 2234 grams and all were admitted to neonatal centers. The most frequent morbidities encountered were respiratory distress (40%). No significant differences in infant characteristics were present between the two cohorts, except for Canadian infants more often requiring respiratory support (53% vs 30%) and caffeine (56% vs 21%), with P < 0.05. The most frequently detected brain lesions were signs of atrophy (28%), IVH (11%) and CBH (11%), with most lesions considered to be mild and no significant differences between cohorts.
Conclusion(s): Our study confirms that MLPT infants, regardless of birth continent, frequently experience neonatal morbidities and brain lesions. Also, it suggests a differing approach to respiratory management across continents. Large cohort studies on the association between morbidities and later adverse outcomes, and the underlying mechanisms, are needed to improve and standardize the clinical care and outcomes of MLPT infants globally.
