Elisabeth Olhager

One-year survival of extremely preterm infants after active perinatal care in sweden

CONTEXT Up-to-date information on infant survival after extremely preterm birth is needed for assessing perinatal care services, clinical guidelines, and parental counseling. OBJECTIVE To determine the 1-year survival in all infants born before 27 gestational weeks in Sweden during 2004-2007. DESIGN, SETTING, AND PATIENTS Population-based prospective observational study of extremely preterm infants (707 live-born and 304 stillbirths) born to 887 mothers in 904 deliveries (102 multiple births) in all obstetric and neonatal units in Sweden from April 1, 2004, to March 31, 2007. MAIN OUTCOME MEASURES Infant survival to 365 days and survival without major neonatal morbidity (intraventricular hemorrhage grade >2, retinopathy of prematurity stage >2, periventricular leukomalacia, necrotizing enterocolitis, severe bronchopulmonary dysplasia). Associations between perinatal interventions and survival. RESULTS The incidence of extreme prematurity was 3.3 per 1000 infants. Overall perinatal mortality was 45% (from 93% at 22 weeks to 24% at 26 weeks), with 30% stillbirths, including 6.5% intrapartum deaths. Of live-born infants, 91% were admitted to neonatal intensive care and 70% survived to 1 year of age (95% confidence interval [CI], 67%-73%). The Kaplan-Meier survival estimates for 22, 23, 24, 25, and 26 weeks were 9.8% (95% CI, 4%-23%), 53% (95% CI, 44%-63%), 67% (95% CI, 59%-75%), 82% (95% CI, 76%-87%), and 85% (95% CI, 81%-90%), respectively. Lower risk of infant death was associated with tocolytic treatment (adjusted for gestational age odds ratio [OR], 0.43; 95% CI, 0.36-0.52), antenatal corticosteroids (OR, 0.44; 95% CI, 0.24-0.81), surfactant treatment within 2 hours after birth (OR, 0.47; 95% CI, 0.32-0.71), and birth at a level III hospital (OR, 0.49; 95% CI, 0.32-0.75). Among 1-year survivors, 45% had no major neonatal morbidity. CONCLUSION During 2004 to 2007, 1-year survival of infants born alive at 22 to 26 weeks of gestation in Sweden was 70% and ranged from 9.8% at 22 weeks to 85% at 26 weeks.

Incidence of and risk factors for neonatal morbidity after active perinatal care : extremely preterm infants study in Sweden (EXPRESS)

Aims:  The aim of this study was to determine the incidence of neonatal morbidity in extremely preterm infants and to identify associated risk factors.

EXPRESS study shows significant regional differences in 1-year outcome of extremely preterm infants in Sweden

The aim of this study was to investigate differences in mortality up to 1 year of age in extremely preterm infants (before 27 weeks) born in seven Swedish healthcare regions.

Studies on human body composition during the first 4 months of life using magnetic resonance imaging and isotope dilution

Assessing body composition during infancy requires data for the so-called reference infant. Currently available data for this purpose need to be updated and extended using methods based on principles different from those used previously to define the reference infant. Thus, magnetic resonance imaging was applied to full-term healthy boys (n = 25) and girls (n = 21), 4–131 d old, to estimate adipose tissue volume (ATV) and the amounts of s.c. and non-s.c. adipose tissue (AT). Total body water was estimated using isotope dilution. Total body fat (TBF), fat free weight (FFW) and the degree of hydration in FFW were calculated. Increases in weight, TBF, and FFW with age agreed with current reference data, although when compared with the reference, a slightly more rapid increase in % TBF was observed for boys. The degree of hydration in FFW was 78.9 ± 4.5% (n = 45). Both sexes showed significant increases with age in s.c. ATV (14.7 and 13.0 mL/d for boys and girls, respectively) and in non-s.c. ATV (1.58 and 1.26 mL/d, respectively). Subcutaneous ATV was 90.5 ± 1.8% (boys) and 91.1 ± 1.9% (girls) of total ATV. In conclusion, a pronounced increase with age in the amount of AT was demonstrated involving a considerable gain in s.c. fat during early life. Except for % TBF in boys, changes in body composition with age agreed with current reference data.

Nutrient intakes independently affect growth in extremely preterm infants: results from a population-based study

To explore associations between energy and macronutrient intakes and early growth in extremely low gestational age (ELGA) infants.

Total energy expenditure, body composition and weight gain in moderately preterm and full-term infants at term postconceptional age.

Aim: To assess total energy expenditure (TEE) and body composition, i.e. total body water (TBW) and adipose tissue volume (ATV), at term age in 8 healthy preterm infants, born between gestational weeks 30 and 33, and in 9 healthy full‐term newborns. Methods: Total and subcutaneous ATVs were assessed using magnetic resonance imaging, while TEE and TBW were estimated using doubly labelled water. Results: Total ATV was 272 ±21 and 261 ± 56 ml/kg body weight, while subcutaneous ATV was 88.9 ± 1.6 and 89.7 ± 2.0% of total ATV for preterm and full‐term infants, respectively. The corresponding figures for TBW (as percentage of body weight) were 67.4 ± 2.5 and 68.1 ± 4.1, respectively. A significant correlation between ATV/kg body weight and body weight was found for full‐term (p < 0.0001) but not for preterm infants. TEE for preterm infants was 315 ± 20 kJ/kg body weight/24 h, which was significantly higher (p < 0.05) than TEE for full‐term infants (254 ± 45 kJ/kg body weight/24 h). At the time of investigation preterm infants weighed significantly (p < 0.05) less (540 g) than full‐term infants. After the time of investigation, weight gains of preterm and full‐term infants were 38 ± 12 and 24 ± 14 g/24 h, respectively.

Description and Evaluation of a Method Based on Magnetic Resonance Imaging to Estimate Adipose Tissue Volume and Total Body Fat in Infants

Information about body fatness is important during nutritional assessment of infants, but current methods to estimate body composition in vivo are often not applicable in infants. Therefore, a new method based on magnetic resonance imaging (MRI) was developed. This method, which can assess the volume and distribution of adipose tissue (AT) as well as total body fat, was applied in 11 healthy full-term infants. Their total body water was also estimated using the isotope dilution technique. Adipose tissue volume (ATV) was calculated from AT area in 16 images of the body taken by an MRI scanner (1.5 tesla). AT area was assessed using a computer program in which AT criteria was defined by the observer. ATV of the infants was therefore evaluated once by three observers and twice by a fourth observer. The different observers estimated total, s.c., and non-s.c. ATV with a precision that varied between 1.9 and 7.2%, 2.0 and 4.8%, and 4.2 and 40.7%, respectively. Variations during AT area calculations accounted for a large part of the imprecision when assessing total and s.c. ATV. The linear relationship between percent total body water and total ATV in relation to body weight was significant in all evaluations. Although average total ATV varied when estimated by the four observers, there was, within each evaluation, a fairly constant order between infants with respect to their ATV. It is concluded that the MRI procedure represents a useful possibility to assess body fatness in infants.

Assessment of total body fat using the skinfold technique in full‐term and preterm infants

BACKGROUND Assessment of body composition may be of interest when the nutritional status of infants is evaluated but is often difficult since simple and valid methods are lacking. With appropriate validation, measurements based on skinfold thickness (SFT) may be useful for this purpose. AIMS To evaluate the potential of a published method, based on measurements of SFT, to assess total body fat (TBF) of infants; and to calculate the fat content of adipose tissue (AT) in infants using previously published information regarding AT volume and total body water. SUBJECTS AND METHODS Forty-five full-term infants and eight infants born in gestational weeks 31-33 were studied at a postnatal age of 4-131 and 44-75 d, respectively. The body water dilution method was used to obtain reference estimates of TBF (TBF-BWD). RESULTS In full-term infants, TBF assessed using the skinfold method (TBF-SFT) minus TBF-BWD was 1.5+/-10.8% (mean+/-2 SD). Furthermore, TBF-SFT minus TBF-BWD (%, y) was correlated (p<0.0001) with the average of TBF-SFT and TBF-BWD (%, x), showing that TBF-SFT was too high in lean infants and too low in infants with more TBF. In the full-term infants, AT contained 0.68+/-0.14 g fat/ml. In the premature infants, TBF-SFT (%), TBF-BWD (%) and the AT fat content were similar to the corresponding figures in nine full-term newborns. CONCLUSION The results indicate that the SFT method produced inaccurate and biased estimates of TBF in infants. A considerable variation between infants regarding their AT fat content may be an important reason for these findings.

Maternal body composition in relation to infant birth weight and subcutaneous adipose tissue

Infant birth weight has increased recently, representing an obstetric and potentially a public health problem since high birth weight involves a risk of obesity later in life. Maternal nutritional status is important for fetal growth and therefore relationships between maternal body weight and composition v. birth weight and infant subcutaneous adipose tissue were investigated in twenty-three healthy women and their newborn infants using multiple and simple linear regression analysis. Furthermore, using previously published data for nineteen infants, it was demonstrated that an anthropometric method could provide useful estimates of the amount of subcutaneous adipose tissue. Birth weight was correlated with the maternal content of total body fat (TBF) both before pregnancy and in gestational week 32 and, together with gestational age at birth, TBF (%) before pregnancy explained 45% of the variation in birth weight. This figure was not increased when gestational gains in weight or TBF were added to the model. Furthermore, in infants, birth weight correlated with the amount of their subcutaneous adipose tissue. Together maternal TBF (%) and amount of subcutaneous adipose tissue in infants explained 61-63% of the variation in birth weight while the amount of infant subcutaneous adipose tissue alone explained only 55%. The maternal TBF content is likely to be important for the recent increase in birth weight. This factor probably causes a general augmentation in fetal growth rather than a specific stimulation of adipose tissue growth.

Time of initiation of skin-to-skin contact in extremely preterm infants in Sweden

Aim:  To describe the time of first skin‐to‐skin contact in extremely preterm infants in a national perspective and to investigate possible factors affecting the time of first skin‐to‐skin contact.