Postnatal growth of preterm born children ≤ 750 g at birth

Abstract

Background Extremely low birth weight (ELBW) infants are at risk of impaired postnatal growth. Impaired postnatal growth has been reported to be associated with delayed cognitive and motor development. Aims To describe postnatal growth patterns of appropriate and small for gestational age (AGA and SGA) ELBW children in relation to their cognitive and motor outcome at age 5.5. Study design Retrospective cohort study. Subjects One hundred one children with a BW ≤ 750 g, born between 1996 and 2005 in the University Hospital Utrecht, The Netherlands. Outcome measures Height (Ht), weight (Wt), occipital–frontal circumference (OFC) at birth, 15 months and 2 years corrected age and 3.5 and 5.5 years. Cognitive and motor outcome at 5.5 years of age, classified as normal (Z-score ≥−1), mildly delayed (−2 ≤ Z-score <−1) or severely delayed (Z-score <−2). AGA (Ht, Wt or OFC at birth ≥−2 SDS) infants were compared with SGA (Ht, Wt or OFC at birth <−2 SDS) infants. Results Between birth and 5.5 years catch-up growth in Ht, weight for height (Wt/Ht), Wt and OFC was seen in 72.2%, 55.2%, 28.6% and 68.9% respectively of the SGA infants. For AGA infants we found substantial catch-down growth in Ht (15.4%) and Wt (33.8%). Cognitive and motor outcome was normal in 76.2% and 41.6% of the 101 children. A significantly higher percentage of normal cognitive outcome was found in AGA infants with Wt growth remaining at ≥−2 SDS compared to AGA infants with catch-down growth (83% vs 63%). Next, SGA infants who caught-up in OFC had a higher prevalence of normal cognitive outcome compared to SGA infants who did not catch-up in OFC. Furthermore, a higher percentage of severely delayed motor outcome was found in SGA infants without catch-up growth in Wt compared to SGA infants who caught-up in Wt (61.5% vs 32.2%). Conclusions Catch-up growth in Ht, Wt/Ht and OFC occurred in the majority of the SGA infants with a BW ≤ 750 g, but was less common in Wt. AGA children who remained their Wt at ≥−2 SDS have a better cognitive and motor developmental outcome at 5.5 years of age. Catch-up growth in OFC was associated with a better cognitive outcome at 5.5 years of age.