Growth Trajectories of Preterm Infants: Birth to 12 Years

Introduction: Birth weight often is used to predict how preterm infants will grow, but scant attention has been paid to the effect of neonatal morbidities on growth trajectories. We investigated birth weight and neonatal morbidity in preterm infants’ growth to age 12 years. Method: A five-group, prospective, longitudinal study was conducted with 194 infants: 46 full term; 29 healthy preterm without morbidity; 56 preterm with medical illness (MPT); 34 preterm with neurologic illness; and 29 preterm small for gestational age (SGA). Height, weight, and body mass index were measured at six ages. Results: The full-term group had greater height than the preterm groups to age 8 years, when healthy preterm and MPT groups caught up. Only the SGA group had smaller height at age 12 years. The MPT, preterm with neurologic illness, and SGA groups had lower weight through age 12 years. Body mass index was appropriate for preterm groups by age 4 years. Across time, neonatal morbidity had a significant effect on height and weight trajectories. Birth weight was significant for weight trajectories only. Discussion: With variation in growth trajectories, details of neonatal morbidity in health history interviews will inform child health assessments

Crescimento de prematuros de extremo baixo peso nos primeiros dois anos de vida Growth of extremely low birth weight infants during the first two years of life

OBJETIVO: Analisar o padrão de crescimento de prematuros de extremo baixo peso (EBP) até 24 meses de idade corrigida, a influência da displasia broncopulmonar (DBP) e os fatores de risco para falha de crescimento. MÉTODOS: Coorte de prematuros <1.000g de gestação única, nascidos e acompanhados em um centro terciário. O crescimento foi avaliado por meio de escores-z para peso, comprimento e perímetro cefálico ao nascimento, com 40 semanas, aos 3, 6, 12, 18 e 24 meses de idade corrigida. Dentre 81 sobreviventes, 70 foram estudados e estratificados em dois grupos: DBP (n=41) e sem DBP (n=29). Foi realizada análise bivariada com teste t ou Mann-Whitney, qui-quadrado ou Exato de Fisher, e análise multivariada com regressão logística. RESULTADOS: Em ambos os grupos, o escore-z de peso diminuiu significantemente entre o nascimento e 40 semanas. Houve um pico de incremento nos escores-z de peso, comprimento e perímetro cefálico entre 40 semanas e três meses. No grupo sem DBP, os escores-z atingiram a faixa normal a partir dos seis meses e assim permaneceram até 24 meses de idade corrigida. Crianças com DBP tiveram menores escores-z de peso e perímetro cefálico no primeiro ano, mas equipararam-se às sem DBP no segundo ano de vida. A regressão logística mostrou que catch-down no escore-z de peso com 40 semanas foi fator de risco para falha de crescimento. CONCLUSÕES: Prematuros EBP apresentam catch-up precoce do crescimento nos primeiros dois anos. Crianças com DBP têm pior crescimento ponderal. A restrição do crescimento pós-natal prediz a falha de crescimento nos primeiros anos.<br>OBJECTIVE: To evaluate the growth pattern of extremely low birth weight infants(ELBW) from birth to 24 months of adjusted gestational age (AA), the influence of bronchopulmonary dysplasia (BPD) and risk factors associated to growth failure. METHODS: This cohort study included all singleton inborn infants with birthweight <1,000g, admitted in the follow-up clinic of a level III Perinatal Center. Weight, length and head circumference were measured at birth, 40 weeks, and 3, 6, 9, 12, 18, 24 months AA, and Z-scores were calculated. Out of the 82 survivors, 70 were studied and classified in two groups: BPD (n=41) and no-BPD (n=29). Statistical analysis included t-test or Mann-Withney, chi-square or Fisher Exact test, and multivariate logistic regression. RESULTS: In both groups, weight z-score decreased significantly between birth and 40 weeks AA. A peak incremental change in weight, length and head circumference z-scores occurred between 40 weeks and three months. Z-scores for the no-BPD group were close to the expected values by the age of six months and remained at these levels at 24 months AA. Children with BPD had lower z-scores for weight and head circumference in the first year of life, but no difference was found between BPD and no-BPD children in the second year of life. Regression analysis showed that catch-down in weight z-score at 40 weeks was a risk factor for failure to thrive. CONCLUSIONS: ELBW infants experienced early catch-up growth during the first two years of life. ELBW with BPD had poor weight gain. Post-natal growth restriction predicts failure to thrive in infancy