Extremely preterm infants who are small for gestational age have a high risk of early hypophosphatemia and hypokalemia.

AIM: Electrolyte balances have not been sufficiently evaluated in extremely preterm infants after early parenteral nutrition. We investigated the risk of early hypophosphatemia and hypokalemia in extremely preterm infants born small for gestational age (SGA) who received nutrition as currently recommended. METHODS: This prospective, observational cohort study included all consecutive extremely preterm infants born at 24-27 weeks who received high amino acids and lipid perfusion from birth. We evaluated the electrolyte levels of SGA infants and infants born appropriate for gestational age (AGA) during the first five days of life. RESULTS: The 12 SGA infants had lower plasma potassium levels from Day One compared to the 36 AGA infants and were more likely to have hypokalemia (58% vs 17%, p = 0.001) and hypophosphatemia (40% vs 9%, p < 0.01) during the five-day observation period. After adjusting for perinatal factors, SGA remained significantly associated with hypophosphatemia (odds ratio 1.39, confidence intervals 1.07-1.81, p = 0.01). CONCLUSION: Extremely preterm infants born SGA who were managed with currently recommended early parenteral nutrition had a high risk of early hypokalemia and hypophosphatemia. Potassium and phosphorus intakes should be set at sufficient levels from birth onwards, especially in SGA infants.

Preterm born 9-year-olds have elevated IGF-1 and low prolactin, but levels vary with behavioural and eating disorders.

AIM: This study examined the relationship between hypothalamic-associated hormones and behavioural and eating disorders in children with low birthweight. METHODS: We included 100 children (mean age 9.7 years): 39 were born preterm at <32 gestational weeks, 28 were full-term, but small for gestational age, and 33 were full-term controls. Behavioural histories were analysed, together with fasting blood samples of leptin, insulin, insulin-like growth factor-1 (IGF-I), prolactin, glucagon and cortisol. RESULTS: Preterm children had lower prolactin (p = 0.01) and higher IGF-I than controls (p < 0.05, adjusted for confounders), despite being significantly shorter than the predicted target height (p < 0.001). More preterm children displayed behavioural disorders (38% versus 10%, p < 0.001) and eating disorders (26% versus 8%, p < 0.05) than full-term children. These disorders were associated with lower leptin (p < 0.01), insulin (p < 0.05) and IGF-I (p < 0.05), but correlations between these hormones and leptin were similar among the groups. Combined behavioural and eating disorders were only observed in preterm children, who were also the shortest in height. CONCLUSION: Behavioural and eating disorders among preterm children were associated with low leptin, insulin and IGF-1. Low prolactin in all preterm children indicated an increased dopaminergic tonus, which might inhibit body weight incrementation. This raises speculation about IGF-I receptor insensitivity.

Improved growth of preterm infants receiving mother's own raw milk compared with pasteurized donor milk.

AIM: To determine whether growth, feeding tolerance and infectious events of preterm infants is related to the proportion of intake of mother's own raw milk (maternal milk) versus pooled pasteurized banked breast milk (donor milk). METHODS: This is a prospective observational study of 55 premature infants born less than 32 weeks of gestational age admitted to the neonatal intensive care unit at the Children's Hospital of Toulouse during two 6-month periods from 2003 to 2005. Enrolled infants were exclusively on enteral feeds with maternal milk ± donor milk. RESULTS: Mean gestational age was 28.6 weeks (SD 1.5) and mean birth weight 1105 grams (SD 282). During the time of exclusively breast milk feeds, weight gain (g/kg/day) was correlated to the proportion of maternal milk consumed (p = 0.0048, r = 0.4). Necrotizing enterocolitis was inversely correlated to the amount of maternal milk. The amount of maternal milk did not impact on infectious events. CONCLUSION: Mother's own raw milk improves weight gain compared with donor milk in preterm infants. Lactation strategies should be sought that helps mothers to increase their milk production.

Predictors of sustained maternal milk feeds in extremely preterm infants.

OBJECTIVE: To investigate the predictors of maternal milk feeds (MMFs) in extremely preterm (EPT) infants during neonatal stay. STUDY DESIGN: Maternal characteristics, obstetrical data and infant characteristics were correlated to MMFs in 97 EPT infants during the first 6 weeks of life and at hospital discharge. RESULT: High MMFs (>90%) at second week predicted sustained MMFs the first 6 weeks of life; nonuniversity education and non-Nordic origin were unfavorable predictors. The proportion of MMFs the first 6 weeks of life and maternal age were positively associated with MMFs at discharge, whereas overweight was an unfavorable predictor. High MMFs at second week, assisted reproduction technology and employment were predictive factors for exclusive MMFs at discharge. CONCLUSION: High MMFs at week 2 promote sustained MMFs in EPT infants and exclusive MMFs at discharge. Mothers who are either young, overweight, non-Nordic or without university education may need special interventions to establish successful lactation.

Moderately preterm infants and determinants of length of hospital stay.

BACKGROUND: Moderately preterm infants account for a large proportion of admissions and bed-days in neonatal units (NU). Management of these infants varies and determinants of length of stay are poorly studied. OBJECTIVE: To determine postmenstrual age at hospital discharge for moderately preterm infants and its relation to perinatal risk factors and to organisation of care. METHODS: Population-based cohort including 2388 infants, born in 2004-2005 with a gestational age (GA) of 30-34 weeks and admitted to 21 NU reporting to the Swedish perinatal register. MAIN OUTCOME: postmenstrual age (PMA) at hospital discharge to home. RESULTS: Mean PMA at hospital discharge was 36.9 (1.7) weeks. High (> or = 35 years) maternal age, multiple birth, small for gestational age, respiratory distress syndrome, infection, hypoglycaemia and hyperbilirubinaemia were significantly associated with higher PMA at discharge, but could only explain 13% of the variation in PMA at discharge. Mean PMA at discharge differed by up to 2 weeks between hospitals. Infants treated at NUs without fixed discharge criteria had 4.7 days lower PMA at discharge and infants receiving domiciliary care had 9.8 days lower PMA at discharge. Breastfed infants also had lower PMA at discharge (mean 2.7 days lower) than those not breast fed, partly explained by lower morbidity in the breastfed infants. CONCLUSIONS: Perinatal risk factors have small overall impact on length of hospital stay in moderately preterm infants. Organisation of care is probably an important factor. The number of bed-days differs significantly between centres, which may have effects on quality of care and health economy.

Increased catecholamines and heart rate in children with low birth weight: perinatal contributions to sympathoadrenal overactivity.

BACKGROUND: Low birth weight is associated with cardiovascular disease. The underlying mechanisms are unknown. We hypothesized that perinatal stress alters autonomic regulation of the cardiovascular system. In this study, catecholamines, heart rate (HR) and blood pressure (BP) were measured in healthy children with low birth weight. METHODS: This clinical study included 105 children (mean age 9.6 years) in three groups; born at term with normal birth weight (controls, n=37), born at term but small for gestational age (SGA, n=29) and born preterm (Preterm, n=39). Dopamine, adrenaline and noradrenaline were determined in urine. HR and BP were measured at rest, during an orthostatic test and after a mathematical mental stress test. RESULTS: Children in the Preterm and SGA groups excreted higher levels of catecholamines when compared with controls. HR (mean [SD] values) were higher at rest and after mental stress in Preterm (at rest 76 [9] and after mental stress 82 [12] min(-1)) and in SGA (79 [8] and 82 [10]) when compared with controls (70 [9] and 75 [9]). HR correlated with urinary catecholamines (r=0.24-0.27, P<0.05). Blood pressures measured at rest, during orthostatic testing and after mental stress did not differ between the groups. CONCLUSIONS: Preterm birth and fetal growth restriction are associated with increased sympathoadrenal activity in childhood, as indicated by stress-induced increases in HR and urinary catecholamines. These findings suggest that the cardiovascular control is differently programmed in these children with possibly higher risk of developing hypertension in adulthood.

Increased blood pressure but normal renal function in adult women born preterm.

UNLABELLED: It has been suggested that children born small for gestational age may develop hypertension and renal dysfunction in adulthood due to impaired fetal kidney development. Very little information on this issue is available on children born preterm. The objective of this study was to investigate the relationship between birth weight, blood pressure, and kidney function in adult subjects who were born preterm or born small for gestational age (SGA). STUDY DESIGN: Subjects (n = 50), all women born between 1966 and 1974, were evaluated at a mean age of 26 +/- 1.9 years. They were allocated to three groups: (1) born before gestational week 32 (n = 15), (2) born full term with birth weight < 2600 g (n = 18) (SGA), and (3) controls, born full term with appropriate birth weight (n = 17). Casual blood pressure, ambulatory 24-h blood pressure (ABPM), glomerular filtration rate (GFR), renal plasma flow (ERPF) and urinary albumin excretion were determined. RESULTS: Preterms had significantly higher casual systolic and mean arterial blood pressure levels compared to controls (123 +/- 13 vs 110 +/- 7 mmHg, P < 0.01, and 87 +/- 9 vs 79 +/- 6 mmHg, P < 0.005, respectively). ABPM was not significantly different between the groups. When the number of systolic recordings > 130 mmHg/subject during ABPM was calculated, the preterms had significantly more recordings above this value (P < 0.05) as well as a significantly increased area under the curve > 130 mmHg and > 140 mmHg systolic (P < 0.05) compared to the controls. SGA subjects were not significantly different from controls. There were no significant differences in GFR, ERPF or urinary albumin excretion between the three groups. CONCLUSION: Women born preterm seem to have a disturbance in blood pressure regulation in adulthood, a finding that is not observed for those born small for gestational age. Kidney function in early adulthood seems to be normal in subjects born preterm or small for gestational age.

Postnatal development of renal function in very low birthweight infants.

The postnatal development of renal function was compared in infants with a gestational age of 25-30 weeks, mean 27.8 weeks (GA 28), and in infants with a gestational age of 31-34 weeks, mean 32.5 weeks (GA 32). The infants were comparable with regard to postnatal course, fluid, caloric and salt intake. Observations were made during the 1st, 2nd and 4th-7th (mean 5th) postnatal weeks. From the 1st to the 5th postnatal week the creatinine clearance (CCr ml/min/1.73 m2), increased from 11 to 20 in GA 28 and from 15 to 30 in GA 32. At 2 weeks of age CCr was significantly lower in GA 28 than in GA 32. During the first week of life diuresis was lower in GA 28 than in GA 32 but thereafter was the same in both groups. We interpret this as a sign of dehydration in GA 28. Serum arginine vasopressin (S-AVP) concentrations were high in both groups at all ages. Mean urine osmolality was low (less than 300) regardless of postnatal age and S-AVP. Urinary sodium excretion was high at 1 week of age in both groups and decreased with increasing postnatal age. Na excretion was slightly higher in GA 28 than in GA 32 at 1 but not at 2 and 5 weeks. UK/UNa was below 1 in both groups during the first week of life and increased with postnatal age. Urinary aldosterone excretion was high in both GA 28 and GA 32 at all ages. Serum sodium levels were lower in GA 28 than in GA 32 at all ages.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal function in sick, very low-birth-weight infants.

Renal immaturity is pronounced in very low-birth-weight infants with a gestational age < or = 30 weeks. We attempted to elucidate if conditions requiring mechanical ventilation, including patent ductus arteriosus, might further compromise renal function due to decreased renal perfusion. Forty infants studied between 4 and 28 days of age were divided into four groups: Control with no patent ductus or mechanical ventilation (n = 8); PDA+MV, with both patent ductus and mechanical ventilation (n = 17); PDA, with patent ductus (n = 6); MV, with mechanical ventilation (n = 9). The groups PDA+MV and MV had significantly lower creatinine clearances and significantly higher fractional sodium excretions than controls. Mean arterial pressure was significantly lower in all groups compared to controls and correlated significantly with creatinine clearance (r = 0.47, p < 0.02). In conclusion, low renal function in these infants is further compromised by a patent ductus arteriosus and/or the use of mechanical ventilation.

Effect of extreme prematurity on renal dopamine and norepinephrine excretion during the neonatal period.

Dopamine (DA), produced in proximal tubular cells, is believed to be an important intrarenal natriuretic hormone. Experimental studies have shown that the natriuretic effect of DA is less pronounced in the fetal kidney. We have evaluated renal DA and norepinephrine (NE) in the neonatal period, using urinary excretion as an indicator of renally produced/released-catecholamines. In very low-birth-weight infants (25-30 weeks gestational age) there was an increase in urinary DA (pmol/mumol urinary creatine) and NE (pmol/mumol urinary creatinine) from 1 to 13 days postnatal age, despite a decrease in sodium excretion. Urinary NE correlated with plasma NE, whereas plasma DA was undetectable. In summary, NE excretion parallels plasma levels and could reflect the general sympathoadrenal activity, whereas DA is primarily of renal origin. Renal DA and NE increase in the first 2 weeks of life in immature infants. We conclude that the catecholamine system of the human kidney undergoes maturational changes postnatally.

IGFBP-1 levels in adult women born small for gestational age suggest insulin resistance in spite of normal BMI.

OBJECTIVE: Impaired fetal development may contribute to decreased insulin sensitivity. This study was designed to characterize serum markers of insulin resistance in adults born small for date or born prematurely. STUDY DESIGN: Fifty subjects, all women, were evaluated at a mean age +/- SD of 26 +/- 2 years (range: 23-30 years). They were allocated to three groups: (i) born fullterm with birth weight <2600 g (n = 18) (small for gestational age, SGA), (ii) born before gestational week 32 (n = 15) (ex-preterm), and (iii) controls, born fullterm with appropriate birth weight (n = 17). Anthropometric data as well as fasting serum samples of plasma B-glucose, serum lipids, insulin, insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-1 (IGFBP-1) levels were determined. RESULTS: In the SGA group final height was lower and they weighed less compared with the controls. Fasting insulin and glucose levels did not differ amongst the groups. Triglycerides were lower in the SGA group and in the ex-preterm group compared with the controls (P < 0.05). The SGA group showed lower IGFBP-1 levels compared with the controls median 17 (range 3-121) vs. 26 (7-67) microg L-1; P < 0.05]. The IGF-I levels in the SGA, ex-preterm and control groups were 212 +/- 58, 259 +/- 37 and 216 +/- 32 microg L-1, respectively, corresponding to a mean SD score of -0.8 +/- 1.0, 0.1 +/- 0.6 and -0.6 +/- 0.6. CONCLUSION: As IGFBP-1 is a marker of insulin sensitivity, the low levels observed in adult women with normal BMI, born small for date, suggest relative insulin resistance in spite of normal BMI.

Renal function in very low birth weight infants: normal maturity reached during early childhood.

Development of glomerular and tubular renal function is delayed in preterm infants. To study the pattern of maturation during infancy and childhood, we re-evaluated renal function in 22 very low birth weight infants--in 14 of the infants at 18 months postconceptional age (9 months corrected age) and in the remaining 8 infants at 8 years of age. The glomerular filtration rate remained lower at 9 months corrected age than in term infants of the same postconceptional age: 82 +/- 23 versus 125 +/- 18 ml/min per 1.73 m2 (p < 0.001). At 8 years of age the glomerular filtration rate did not differ from that of healthy control subjects. Effective renal plasma flow, filtration fraction, albumin excretion, maximal concentrating ability, and kidney size determined by ultrasonography were all normal at 8 years of age. We conclude that renal function, which is markedly reduced during the neonatal period in very low birth weight infants, reaches normal maturity by 8 years of age but not by 9 months corrected age.