Growth Restriction In Preterm Infants Research Articles

Cardiac hypertrophy and altered hemodynamic adaptation in growth-restricted preterm infants.

The objective was to elucidate hemodynamic adaptation in very low birth weight (<1500 g) infants after intrauterine growth retardation. 31 growth-retarded (SGA, birth weight <-2 SD) and 32 appropriate for gestational age (AGA, birth weight within +/- 1 SD range) infants were enrolled. In SGA infants, the diastolic diameters of the interventricular septum and the left ventricle were increased, and serum brain natriuretic peptide (BNP) was elevated. Left ventricular output (LVO) of the AGA infants increased from 150 +/- 28 to 283 +/- 82 mL/kg/min during the study (p < 0.01). The SGA infants had a higher initial LVO than the AGA infants (243 +/- 47 versus 150 +/- 28 mL/kg/min, p < 0.05), but did not show further LVO increase during the study period. Red cell (RCV) and blood (BV) volume were assessed by Hb subtype analysis, when packed donor red cells were transfused. RCV and BV did not differ between the groups initially, but RCV increased by 18% and BV by 29% in the AGA group during the first 3 d. On day 3, AGA infants had larger BV than the SGA infants (88 +/- 5 versus 73 +/- 12 mL/kg, p < 0.05). In conclusion, cardiac hypertrophy, elevated initial LVO and BNP of the SGA infants suggest increased cardiac workload after intrauterine growth retardation. Based on the BV and RCV data, blood volume regulation may also be impaired. The data suggest that SGA preterm infants may be exposed to an increased risk of circulatory failure during early adaptation.

Fetal Growth and the Function of the Adrenal Cortex in Preterm Infants

Small for gestational age preterm infants have a higher risk of neonatal morbidity compared to appropriate for gestational age preterm infants. A diminished adrenal response to stress may be involved in the higher postnatal morbidity. The adrenal cortex response in relation to fetal growth was studied by ACTH stimulation tests in 43 preterm infants (born ≤32 wk). The cortisol and 17-hydroxyprogesterone (17-OHP) responses to 1 μg/kg ACTH were analyzed in relation to birth weight sd scores (BW-SDS) corrected for gestational age, gender, and parity. BW-SDS was significantly associated with the cortisol and 17-OHP response. Infants with the lowest BW-SDS had the lowest cortisol levels after stimulation. No effect of size at birth was found on the ratio between cortisol and 17-OHP. In addition, basal cortisone levels in a single blood sample were higher in infants with the lowest BW-SDS than in infants with higher BW-SDS, but the ratio between cortisol and cortisone was comparable in the two groups. We conclude that the response of cortisol and 17-OHP to ACTH stimulation in preterm infants is related to fetal growth. The lack of influence of fetal growth on the ratio between cortisol and 17-OHP after ACTH stimulation suggests that the activities of 21- and 11β-hydroxylase are not affected. The lower adrenal response to stimulation may be important in neonatal morbidity and possibly the development of disease in later life in growth-restricted preterm infants.

Fetal growth and the function of the adrenal cortex in preterm infants.

Small for gestational age preterm infants have a higher risk of neonatal morbidity compared to appropriate for gestational age preterm infants. A diminished adrenal response to stress may be involved in the higher postnatal morbidity. The adrenal cortex response in relation to fetal growth was studied by ACTH stimulation tests in 43 preterm infants (born < or = 32 wk). The cortisol and 17-hydroxyprogesterone (17-OHP) responses to 1 microg/kg ACTH were analyzed in relation to birth weight SD scores (BW-SDS) corrected for gestational age, gender, and parity. BW-SDS was significantly associated with the cortisol and 17-OHP response. Infants with the lowest BW-SDS had the lowest cortisol levels after stimulation. No effect of size at birth was found on the ratio between cortisol and 17-OHP. In addition, basal cortisone levels in a single blood sample were higher in infants with the lowest BW-SDS than in infants with higher BW-SDS, but the ratio between cortisol and cortisone was comparable in the two groups. We conclude that the response of cortisol and 17-OHP to ACTH stimulation in preterm infants is related to fetal growth. The lack of influence of fetal growth on the ratio between cortisol and 17-OHP after ACTH stimulation suggests that the activities of 21- and 11 beta-hydroxylase are not affected. The lower adrenal response to stimulation may be important in neonatal morbidity and possibly the development of disease in later life in growth-restricted preterm infants.

Neonatal outcome in growth-restricted versus appropriately grown preterm infants.

The objective of this paper is to examine whether growth-restricted preterm infants have a different neonatal outcome than appropriately grown preterm infants. All consecutive, singleton preterm deliveries between 27-35 weeks' gestation were included over a 4-year period. Infants with congenital anomalies and infants of diabetic mothers were excluded. Infants were categorized as small-for-gestational-age (SGA) when birth weight was at or below the 10th percentile, and appropriate-for-gestational-age (AGA) when between the 11th and 90th percentiles. Outcome variables included: neonatal death, respiratory distress syndrome (RDS), sepsis, intraventricular hemorrhage (IVH), and necrotizing enterocolitis (NEC). Neonatal morbidity and mortality were examined by univariate and stepwise multivariate logistic regression analyses. Factors controlled for during the analysis included: maternal age; gestational age; mode of delivery; presence of preeclampsia, HELLP syndrome, prolonged premature rupture of membranes (PROM), placental abruption, placenta previa, prenatal steroid exposure, infant gender, and low Apgar score. Seventy-six infants were included in the SGA group and 209 in the AGA group. SGA infants had a higher mortality rate (p = 0.003). They also had more culture-proven sepsis episodes (p = 0.001). No differences were found with respect to the other outcomes. The results were similar when analyzed separately for the group of infants born at or below 32 weeks' gestation. Growth-restricted preterm infants were found to have both higher mortality and infection rates compared with AGA preterm infants. Growth restriction in the preterm neonate was not found to protect against other neonatal outcomes associated with prematurity. When considering elective preterm delivery for this high-risk group of pregnancies, the increased risks in the neonatal period should be taken into account.