Mireille Vanpée

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

Abstract 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.

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.

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.

Resuscitation and ventilation strategies for extremely preterm infants: a comparison study between two neonatal centers in Boston and Stockholm

Aim: To evaluate if different resuscitation and ventilatory styles exist between two neonatal units, and if the less aggressive approach has a beneficiary effect on BPD outcome.

Postnatal Development of Renal Function in Very Low Birth weight Infants

ABSTRACT. 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 (<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. Hyponatremia was observed in 13/32 infants in GA 28 and in 1/45 infants in GA 32. We conclude that the postnatal development of renal function is retarded in all preterm infants and is slightly slower in infants with a GA below 31 weeks than in infants with a GA of 31–34 weeks. Extrarenal factors must contribute to the low serum Na values in infants with GA <31 weeks.

Early hyperglycemia is a risk factor for death and white matter reduction in preterm infants.

OBJECTIVE: The objective of this study was to determine whether hyperglycemia during the first week of life in extremely preterm (EPT) infants was associated with increased mortality rates and with cerebral injury, as assessed with MRI of the brain, at term-equivalent age. METHODS: All 143 EPT infants (gestational ages of <27 weeks) who were born at Karolinska University Hospital between January 2004 and December 2006 and were alive at 24 hours were eligible. Of the 118 surviving infants, 24 were excluded for various reasons. MRI was performed for the 94 included survivors at term age, with a 1.5-T system, and scans were scored for gray matter/white matter (WM) abnormalities. Of the 25 infants who died before term age, 6 were excluded because of missing glucose documentation and the remaining 19 were included. Hyperglycemia was defined as plasma glucose levels of >8.3 mmol/L. RESULTS: Hyperglycemia occurring on the first day of life was identified as an independent risk factor for death (adjusted odds ratio: 3.7 [95% confidence interval: 1.3–10.6]; P = .01). Hyperglycemia occurring on the first day of life also was a risk factor for WM reduction, as determined through MRI, at term-equivalent age (adjusted odds ratio: 3.1 [95% confidence interval: 1.0–9.2]; P = .04). CONCLUSION: In this population-based cohort of EPT infants, hyperglycemia on the first day of life was associated with increased mortality rates and brain damage, as reflected by WM reduction at term age.

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).

Neonatal Morbidity in Moderately Preterm Infants: A Swedish National Population-Based Study

OBJECTIVE To determine the gestational age (GA)-specific risks for neonatal morbidity and use of interventions in infants born at 30 to 34 completed gestational weeks. STUDY DESIGN A population-based Swedish study including 6674 infants born during 2004-2008. Risks for neonatal morbidity and use of interventions were investigated with respect to GA and birth weight standard deviation scores. RESULTS Acute lung disorder was diagnosed in 28%, hypoglycemia in 16%, bacterial infection in 15% and hyperbilirubinemia in 59% of the infants. Thirty-eight percent had received antenatal steroid therapy, 43% nasal continuous positive airway pressure, 5.5% required mechanical ventilation, 5.2% were treated with surfactant, and 30% with antibiotic therapy. Neonatal morbidity rates increased with decreasing GA, with odds ratios for different outcomes ranging from 2.1 to 23 at 30 weeks compared with 34 weeks of GA. Low birth weight standard deviation scores was more common at lower GA and was associated with increased morbidity rates. CONCLUSIONS Despite general advances in perinatal care, moderately preterm infants still have substantially increased risks for neonatal morbidity. Whereas the neonatal morbidity rate was similar to results of previous reports, management of respiratory problems differed markedly from other studies.

Breastmilk handling routines for preterm infants in Sweden: a national cross-sectional study.

BACKGROUND In Sweden preterm infants born <32 gestational weeks are fed maternal breastmilk or, if not available, donor breastmilk. Nutritional and immunological composition of human milk is affected by processing and storage procedures. Additionally, freezing of breastmilk may reduce cytomegalovirus transmission. The present recommendations for human milk use in Sweden are outdated. However, new guidelines to standardize routines are underway. This study was designed to document current routines pertaining to breastmilk use for preterm infants in Sweden. METHODS A questionnaire regarding breastmilk handling and routines was sent to all 36 neonatal units in Sweden in November 2006 and February 2007. RESULTS Of the 36 participating neonatal units 27 had their own milk bank. Milk donors were screened for human immunodeficiency virus, human T-lymphotropic virus, and hepatitis B and C viruses by 27, 14, and 22 of the milk banks, respectively. Bacterial culture was performed on donor milk in 24 milk banks. Donor milk was pasteurized in 22 milk banks. In 11 of the 36 neonatal units maternal milk was frozen to reduce the risk of cytomegalovirus transmission. No neonatal unit performed bacterial culture or pasteurization of maternal milk. Breast milk was kept frozen for a maximum of 3-6 months before use. Nutritional analysis of donor and/or maternal milk was performed in 25 units. All neonatal units enriched donor milk and maternal milk. CONCLUSIONS Routines for breastmilk handling differ among the 36 neonatal units in Sweden. New guidelines can standardize the handling of human milk, thereby improving nutrition and minimizing the risk of breastmilk-induced infection in the preterm infant.

Renal function in sick, very low‐birth‐weight infants

Renal immaturity is pronounced in very low‐birth‐weight infants with a gestational age 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.