Being parents of extremely preterm children, from a long-term perspective: A qualitative study of parents' experiences.

BACKGROUND: In recent decades, modern neonatal intensive care has improved, increasing the survival of extremely preterm children. Few studies have examined the experiences of parents of extremely preterm children from a long-term perspective. AIM: To describe parents' experiences of parenting extremely preterm children during their childhood and transition to adulthood. STUDY DESIGN: A qualitative interview study with a descriptive design. SUBJECTS: Thirteen parents of eleven children born at 24 gestational weeks in Sweden, 1990-1992, participated in individual semi-structured interviews. OUTCOME MEASURES: Data were analyzed using qualitative reflexive thematic analysis. RESULT: Five themes forming a timeline were created in the analytic process: parenthood, at the NICU, young childhood, adolescence, and adulthood. Various aspects affecting parenthood were described throughout the timeline, and occasionally the parents experienced difficulties dealing with their children's special physical and/or mental needs. Today, some families have established a functioning situation despite their children's physical and/or mental difficulties, while some still struggle with their children's everyday life. CONCLUSION: Having an extremely preterm family member profoundly affects the whole family for various lengths of time. Parents expressed a need for support from both healthcare and school throughout their children's childhood and in their transition to adulthood, although the need varies between parent-child pairs. By studying the parents' experiences, their need for support can be further recognized and understood, and developed and improved accordingly.

Lipid Peroxidation and Antioxidative Capacity Are Unaltered in Transitional Breast Milk Exposed to Light from Women Giving Birth to Preterm Infants before 32 Weeks of Gestation.

Breast milk (BM) is the primary nutrition for infants and has a high content of lipids. Preterm infants receive expressed BM via tube feeding, and they are frequently treated with phototherapy. When parenteral nutrition (PN) is exposed to light and/or phototherapy, lipid peroxidation (LPO) increases. By light-protecting PN, morbidity and mortality are reduced in preterm infants through the reduction of oxidative stress. We aimed to investigate whether light-protecting breast milk could reduce LPO. Twelve mothers giving birth to a preterm infants of less than 32 weeks of gestational age were included. Transitional BM was collected and divided into three study groups; light-protected, ward light and phototherapy light. Baseline samples were collected after expression and the exposures started within one hour. Feeding syringe samples were exposed to light for 30 up to 360 min. Nasogastric tube samples were run through a tube under the same light conditions. Samples were stored in -80 °C until analyses of malondialdehyde (MDA), 4-hydroxynonenal (4-HNE) and total antioxidant capacity (TAC). There were no significant differences in MDA, 4-HNE or TAC levels observed between the different study groups. This study indicates that the light exposure of expressed transitional BM does not affect LPO and the levels of MDA, 4-HNE or TAC.

To Feel Abandoned in an Insecure Situation: Parents' Experiences of Separation From Their Newborn Due to the Mother Being COVID-19 Positive.

BACKGROUND: The COVID-19 pandemic resulted in changes in neonatal care, sometimes resulting in a separation between parents and their newborn. Knowledge about parents' experiences of this separation is limited. PURPOSE: To explore parents' experiences of separation from their newborn due to COVID-19. METHODS: Interviews with parents (n = 11) separated from their newborn. RESULTS: The parents' experiences of being separated from their newborn were expressed under 3 themes: "To create a sense of safety in an insecure situation"; "Unexpected start to parenthood"; and "To be reunited." Parents felt abandoned and alone, even if they had support from significant others. Although they considered the separation as undesired, wanting to be with their newborn infant, it was secondary to not wanting to infect the infant with COVID-19. Furthermore, lacking information about a potentially lethal virus adds to the uncertainty that comes with having a newborn. The separation affected the whole family, some for a long time afterward. IMPLICATIONS FOR PRACTICE AND RESEARCH: If a new situation with potentially life-threatening effects, like the COVID-19 pandemic, occurs again, considering the experiences of these parents is paramount. Precautions should be taken to minimize the potential harm. If a separation between newborns and parents is inevitable, parents need preparation and transparent information prior to the separation and before the reunion. Well-thought-out policies must be in place to minimize the impact of a separation on both parties. Parents should be able to have a deputy parent present during an undesired but necessary separation from their newborn.

Early Hyperglycemia in Very Preterm Infants Is Associated with Reduced White Matter Volume and Worse Cognitive and Motor Outcomes at 2.5 Years.

INTRODUCTION: Hyperglycemia in very preterm infants is associated with increased morbidity and mortality. We aimed to investigate potential associations between early hyperglycemia, neonatal cerebral magnetic resonance imaging (MRI), and neurodevelopment at 2.5 years. METHODS: The study population included 69 infants with gestational age (GA) 22.3-31.9 weeks (n = 29 with GA <28 weeks), born 2011-2014. Plasma glucose concentrations during the first week were checked according to clinical routines. Hyperglycemia was defined as glucose concentrations above 8.3 mmol/L (150 mg/dL) and above 10 mmol/L (180 mg/dL), respectively, categorized as the highest glucose days 0-2, number of days above 8.3 and 10 mmol/L, and prolonged (yes/no) 2 days or more above 8.3 and 10 mmol/L. The MRI analysis included morphological assessment, regional brain volumes, and assessment of apparent diffusion coefficient (ADC). Neurodevelopmental impairment (NDI) developed in 13 of 67 infants with available outcomes, of which 57 were assessed with the Bayley-III. Univariate and multiple linear and logistic regressions were performed with adjustments for GA, birth weight z-scores, and illness severity expressed as days on mechanical ventilation. RESULTS: Hyperglycemia above 8.3 mmol/L and 10 mmol/L was present in 47.8% and 31.9% of the infants. Hyperglycemia correlated independently with lower white matter volume, but not with other regional brain volumes, and was also associated with lower ADC values in white matter. Hyperglycemia also correlated with lower Bayley-III cognitive and motor scores in infants with GA <28 weeks, but there was no significant effect on NDI. CONCLUSION: Early hyperglycemia is associated with white matter injury and poorer neurodevelopment in very preterm infants.

The Impact of Restricted versus Liberal Early Fluid Volumes on Plasma Sodium, Weight Change, and Short-Term Outcomes in Extremely Preterm Infants.

The optimal fluid requirements for extremely preterm infants are not fully known. We examined retrospectively the fluid intakes during the first week of life in two cohorts of extremely preterm infants born at 22-26 weeks of gestation before (n = 63) and after a change from a restrictive to a more liberal (n = 112) fluid volume allowance to improve nutrient provision. The cohorts were similar in gestational age and birth weight, but antenatal steroid exposure was more frequent in the second era. Although fluid management resulted in a cumulative difference in the total fluid intake over the first week of 87 mL/kg (p < 0.001), this was not reflected in a mean weight loss (14 ± 5% at a postnatal age of 4 days in both groups) or mean peak plasma sodium (142 ± 5 and 143 ± 5 mmol/L in the restrictive and liberal groups, respectively). The incidences of hypernatremia (>145 and >150 mmol/L), PDA ligation, bronchopulmonary dysplasia, and IVH were also similar. We conclude that in this cohort of extremely preterm infants a more liberal vs. a restricted fluid allowance during the first week had no clinically important influence on early changes in body weight, sodium homeostasis, or hospital morbidities.

Amino acid infusions in umbilical artery catheters enhance protein administration in infants born at extremely low gestational age.

AIM: It is challenging to provide extremely low gestational age neonates (ELGANs) with adequate protein supply. This study aimed to investigate whether amino acid (AA) infusion in the umbilical artery catheter (UAC) in ELGANs is safe and enhances protein supply and growth. METHOD: A before and after study including infants born <27 weeks, treated in Uppsala, Sweden, during 2004-2007, compared those receiving normal saline/10% dextrose in water with those receiving AA infusion in the UAC. Data were retrieved from the Extremely Preterm Infants in Sweden Study, hospital records and the Swedish Neonatal Quality Register. Group comparisons, univariate and multivariate analyses were conducted. RESULTS: AA group (n = 41, females 39%) received on average approximately 0.3 g/kg/day more protein during the first postnatal week, compared to control group (n = 30, females 40%) (unstandardised coefficient (B) 0.26, p .001) but no difference was noted during 8-28 postnatal days. The type of infusion was not associated with growth variables. The incidence of neonatal morbidities and UAC-related thrombosis did not differ between the groups. CONCLUSION: AA infusions in the UACs in ELGANs is safe and enhances protein supply during the first postnatal week. However, this practice is not associated with growth during the first 28 postnatal days.

The Risk of Necrotizing Enterocolitis following the Administration of Hyperosmolar Enteral Medications to Extremely Preterm Infants.

INTRODUCTION: Necrotizing enterocolitis (NEC) is a disease predominantly affecting preterm infants. The administration of hyperosmolar solutions could lead to the development of NEC. The objective of this study was to measure the osmolality of enteral medications used in clinical practice and to assess the risk of NEC following exposure to hyperosmolar medications. METHODS: A retrospective cohort study in extremely preterm infants (gestational age <28 weeks) born between 2010 and 2016 at a tertiary neonatal intensive care unit in Sweden. 465 infants were identified via the Swedish Neonatal Quality register. Data relating to enteral administrations received during a two-week period were collected from the medical records. The osmolalities of medications were measured using an osmometer. Logistic regression was used to calculate the odds ratio of developing NEC. RESULTS: A total of 253 patients met the inclusion criteria. The osmolalities of 5 commonly used medications significantly exceeded the recommended limit of 450 mOsm/kg set by the American Academy of Paediatrics (AAP). Most patients (94%) received at least one hyperosmolar medication. No significant risk of developing NEC could be found. CONCLUSION: The medications used in clinical practice can significantly exceed the limit set by the AAP. This study does not indicate an increased risk of developing NEC in extremely preterm infants following exposure to hyperosmolar medications. Further studies in larger cohorts are needed to determine the specific cut-off level of osmolality in relation to the pathogenesis of NEC.

"Paying it Forward" - Swedish Women's Experiences of Donating Human Milk.

BACKGROUND: Human milk is recommended as the only nutritional source during the first 6 months of life. For preterm infants, the benefits of human milk are even more important and can alleviate the negative influences of preterm birth. RESEARCH AIM: To describe how Swedish human milk donors experienced the donation process. METHOD: A prospective mixed methods mail survey was designed. It was sent to human milk donors (N = 72) at two Swedish hospitals. Quantitative data are presented with descriptive statistics and qualitative data were analyzed using qualitative content analysis. RESULTS: The infants were between newborn and 17 weeks of age when the participants started their human milk donations, and the duration of the donation period lasted 1-24 weeks. The overall theme identified was the participants' strong desire to help infants, often expressed as being involved in saving infants' lives. Many participants experienced difficulties getting the information needed to become human milk donors; for others, expressing milk required both time and energy that they could otherwise spend with their own newborn infants. CONCLUSION: Donating human milk can be experienced as a demanding and strenuous task. Therefore, it is important that women who donate human milk receive the practical help from health care staff that they feel they need. Furthermore, information and knowledge about the possibility of donating human milk, and how important human milk is for preterm and/or sick infants, are important in order to increase the number of women willing to donate human milk.

Perfluoroalkyl acid levels in first-time mothers in relation to offspring weight gain and growth.

We investigated if maternal body burdens of perfluoroalkyl acids (PFAAs) at the time of delivery are associated with birth outcome and if early life exposure (in utero/nursing) is associated with early childhood growth and weight gain. Maternal PFAA body burdens were estimated by analysis of serum samples from mothers living in Uppsala County, Sweden (POPUP), sampled three weeks after delivery between 1996 and 2011. Data on child length and weight were collected from medical records and converted into standard deviation scores (SDS). Multiple linear regression models with appropriate covariates were used to analyze associations between maternal PFAA levels and birth outcomes (n=381). After birth Generalized Least Squares models were used to analyze associations between maternal PFAA and child growth (n=200). Inverse associations were found between maternal levels of perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA), and birth weight SDS with a change of -0.10 to -0.18 weight SDS for an inter-quartile range (IQR) increase in ng/g PFAA. After birth, weight and length SDS were not significantly associated with maternal PFAA. However, BMI SDS was significantly associated with PFOA, PFNA, and PFHxS at 3 and 4years of age, and with PFOS at 4 and 5years of age. If causal, these associations suggest that PFAA affects fetal and childhood body development in different directions.

Maternal rates of lipolysis and glucose production in late pregnancy are independently related to foetal weight.

OBJECTIVE: Associations between maternal glucose levels and increased foetal growth are well established, and independent relationships with maternal weight, weight gain and insulin resistance are also observed. The relative roles of lipolysis and glucose production in the determination of these observations remain unclear. DESIGN: We examined, through detailed physiological studies, the relationship between maternal late gestational energy substrate production (glucose and glycerol), maternal weight and weight gain, and estimated foetal size in the third trimester. PATIENTS: Twenty-one nulliparous pregnant women, without gestational diabetes (GDM) assessed at 28 weeks with oral glucose tolerance test, were recruited. MEASUREMENTS: Rates of hepatic glucose production (GPR) and rates of glycerol production (reflecting lipolysis) using [13 C6 ]-glucose and [2 H5 ]-glycerol were measured at 34-36 weeks of gestation. Respiratory quotient was assessed by indirect calorimetry and body composition by measurements of total body water (TBW; H218 O) and body density (BODPOD). Foetal weight was estimated from ultrasound measures of biparietal diameter, femoral length and abdominal circumference. RESULTS: At 34-36 weeks, bivariate analyses showed that GPR and lipolysis correlated with estimated foetal weight (r=.71 and .72, respectively) as well as with maternal weight, fat mass and fat-free mass, but not maternal weight gain. In multivariate analyses, rates of both glucose production (r=.42) and lipolysis (r=.47) were independently associated with foetal size explaining 63% of the variance. CONCLUSIONS: Both maternal rates of lipolysis and hepatic glucose production in late gestation are strongly related to estimated foetal weight.

Obesity rates in two generations of Swedish women entering pregnancy, and associated obesity risk among adult daughters.

We examined changes in obesity rates in two generations of Swedish women entering pregnancy, and assessed the effects of maternal body mass index (BMI) on the risk of overweight or obesity among adult daughters. This study covered an intergenerational retrospective cohort of 26,561 Swedish mothers and their 26,561 first-born daughters. There was a 4-fold increase in obesity rates, which rose from 3.1% among women entering pregnancy in 1982-1988 to 12.3% among their daughters in 2000-2008 (p < 0.0001) when entering pregnancy. The greater the maternal BMI, the greater the odds of overweight and/or obesity among daughters. Underweight mothers had half the odds of having an overweight or obese daughter in comparison to mothers of normal BMI (p < 0.0001). In contrast, the odds ratio of obese mothers having obese daughters was 3.94 (p < 0.0001). This study showed a strong association between maternal obesity and the risk of obesity among their first-born daughters. In addition, we observed a considerable increase in obesity rates across generations in mother-daughter pairs of Swedish women entering pregnancy. Thus, it is important to have preventative strategies in place to halt the worsening intergenerational cycle of obesity.

Adipokines and their relation to maternal energy substrate production, insulin resistance and fetal size.

OBJECTIVE: The role of adipokines in the regulation of energy substrate production in non-diabetic pregnant women has not been elucidated. We hypothesize that serum concentrations of adiponectin are related to fetal growth via maternal fat mass, insulin resistance and glucose production, and further, that serum levels of leptin are associated with lipolysis and that this also influences fetal growth. Hence, we investigated the relationship between adipokines, energy substrate production, insulin resistance, body composition and fetal weight in non-diabetic pregnant women in late gestation. STUDY DESIGN: Twenty pregnant women with normal glucose tolerance were investigated at 36 weeks of gestation at Uppsala University Hospital. Levels of adipokines were related to rates of glucose production and lipolysis, maternal body composition, insulin resistance, resting energy expenditure and estimated fetal weights. Rates of glucose production and lipolysis were estimated by stable isotope dilution technique. RESULTS: Median (range) rate of glucose production was 805 (653-1337) µmol/min and that of glycerol production, reflecting lipolysis, was 214 (110-576) µmol/min. HOMA insulin resistance averaged 1.5 ± 0.75 and estimated fetal weights ranged between 2670 and 4175 g (-0.2 to 2.7 SDS). Mean concentration of adiponectin was 7.2 ± 2.5mg/L and median level of leptin was 47.1 (9.9-58.0) µg/L. Adiponectin concentrations (7.2 ± 2.5mg/L) correlated inversely with maternal fat mass, insulin resistance, glucose production and fetal weight, r=-0.50, p<0.035, r=-0.77, p<0.001, r=-0.67, p<0.002, and r=-0.51, p<0.032, respectively. Leptin concentrations correlated with maternal fat mass and insulin resistance, r=0.76, p<0.001 and r=0.73, p<0.001, respectively. There was no correlation between maternal levels of leptin and rate of glucose production or fetal weight. Neither were any correlations found between levels of leptin or adiponectin and maternal lipolysis or resting energy expenditure. CONCLUSION: The inverse correlations between levels of maternal adiponectin and insulin resistance as well as endogenous glucose production rates indicate that low levels of adiponectin in obese pregnant women may represent one mechanism behind increased fetal size. Maternal levels of leptin are linked to maternal fat mass and its metabolic consequences, but the data indicate that leptin lacks a regulatory role with regard to maternal lipolysis in late pregnancy.

Insulin resistance, a link between maternal overweight and fetal macrosomia in nondiabetic pregnancies.

BACKGROUND/AIMS: During the last decades the number of large for gestational age infants delivered by nondiabetic mothers has increased. Our aim was to investigate to what extent fetal growth in nondiabetic pregnant women can be explained by rates of maternal energy substrate production and resting energy expenditure. METHODS: Twenty nonsmoking pregnant women without impaired glucose tolerance and with a wide range of fetal weights (0.2-2.7 SDS) were investigated at 36 weeks of gestation. Maternal lipolysis, glucose production, resting energy expenditure, body composition and insulin resistance were assessed. RESULTS: Median (range) glucose production rate was 805 (653-1,337) µmol/min and that of glycerol, reflecting lipolysis, was 214 (110-576) µmol/min. Multiple linear regression analysis showed that maternal fat mass explained 36% of the variation in insulin resistance, accounting for 62% of the variation in glucose production. Further, glucose production explained 31% of the variation in fetal weight. Resting energy expenditure explained 51% of the variation in estimated fetal weight. CONCLUSION: Fetal weight is dependent on maternal glucose production, which is in turn determined by the degree of insulin resistance, induced in part by the maternal fat mass. The variation in maternal resting energy expenditure is closely related to fetal weight.

Perinatal energy metabolism with reference to IUGR & SGA: studies in pregnant women & newborn infants.

Glucose is the most important fetal energy substrate. During the third trimester increased maternal glucose production and insulin resistance improves fetal glucose availability. Maternal malnutrition, chronic disease and/or placental dysfunction can disturb glucose delivery, resulting in intrauterine growth restriction (IUGR) and an infant born small for gestational age (SGA). Hypoglycaemia is a problem frequently occurring in infants born SGA; they are also at long-term risk of developing insulin resistance. In the studies presented, energy substrate production was investigated using stable isotope dilution technique, in normal pregnancies and pregnancies complicated by intrauterine growth restriction (IUGR). In addition energy substrate production in infants born SGA was studied on their first day of life. We found that late pregnancy was associated with an almost twofold increase in rate of lipolysis. This provides substrates for maternal energy metabolism, sparing glucose for the fetus. Even though glucose production was comparable in the two groups of pregnant women, those with IUGR had a lower rate of lipolysis. A reduced supply of energy substrates could be one factor underlying IUGR. In spite of the insulin resistance of late gestation, insulin still had a regulatory role in energy substrate production in the women with normal pregnancies, but not in those with IUGR. Although infants born SGA have limited energy stores, we demonstrated that they are capable of both lipolysis and glucose production. Data on insulin and IGFBP-1 in the SGA infants indicate that insulin sensitivity is increased peripherally but reduced in the liver.

Pregnancy insulin, glucose, and BMI contribute to birth outcomes in nondiabetic mothers.

OBJECTIVE: We investigated the effects of normal variations in maternal glycemia on birth size and other birth outcomes. RESEARCH DESIGN AND METHODS: Women in two unselected birth cohorts, one retrospective (n = 3,158) and one prospective (n = 668), underwent an oral glucose challenge at 28 weeks of gestation. In the retrospective study, glycemia was linked to routine birth records. In the prospective study, offspring adiposity was assessed by skinfold thickness from birth to age 24 months. RESULTS: In the retrospective study, within the nondiabetic range (2.1-7.8 mmol/l), each 1 mmol/l rise in the mother's 60-min glucose level was associated with a (mean +/- SEM) 2.1 +/- 0.8% (P = 0.006) rise in absolute risk of assisted vaginal delivery, a 3.4 +/- 0.8% (P < 0.0001) rise in emergency cesarean delivery, a 3.1 +/- 0.7% (P < 0.0001) rise in elective cesarean delivery, and a 46 +/- 8 g (P < 0.0001) increase in offspring birth weight. In the prospective study, fetal macrosomia (birth weight >90th centile) was independently related to the mother's fasting glucose (odds ratio 2.61 per +1 mmol/l [95% CI 1.15-5.93]) and prepregnancy BMI (1.10 per +1 kg/m(2) [1.04-1.18]). The mother's higher fasting glycemia (P = 0.004), lower insulin sensitivity (P = 0.01), and lower insulin secretion (P = 0.02) were independently related to greater offspring adiposity at birth. During postnatal follow-up, the correlation between the mother's glycemia and offspring adiposity disappeared by 3 months, whereas prepregnancy BMI was associated with offspring adiposity that was only apparent at 12 and 24 months (both P < 0.05). CONCLUSIONS: Prepregnancy BMI, pregnancy glycemia, insulin sensitivity, and insulin secretion all contribute to offspring adiposity and macrosomia and may be separate targets for intervention to optimize birth outcomes and later offspring health.

Insulin and carbohydrate metabolism.

Fetal glucose exposure and consequent fetal insulin secretion is normally tightly regulated by glucose delivery from the mother during pregnancy. Maternal hyperglycaemia and gestational diabetes (GDM) are known to be detrimental to offspring, although defining the criteria for diagnosis of GDM is controversial. Recent data suggest that the risk of poor fetal outcome appears to be a continuous variable across the range of glucose control, and that the level of maternal blood glucose for a diagnosis of gestational diabetes needs to be reviewed. After birth, rapid adaptation is necessary for infants to be able to maintain independent glucose homeostasis. This adaptation is compromised in infants who are small for gestational age (SGA), premature, or large for gestational age (LGA). Interestingly, the infants who are born at the extremes of birth weight are also at increased risk of impaired glucose tolerance and diabetes in later life.

Lipolysis and insulin sensitivity at birth in infants who are large for gestational age.

OBJECTIVE: In addition to neonatal hypoglycemia, infants who are born large for gestational age are at risk for developing obesity, cardiovascular disease, and diabetes later in life. The aim of this study was to investigate glucose production, lipolysis, and insulin sensitivity in infants who were born large for gestational age to mothers without diabetes. The effect of glucagon administration on production of energy substrates was also investigated. METHODS: Ten healthy term infants who were born large for gestational age to mothers without diabetes were studied 16 +/- 8 hours postnatally after a 3-hour fast. Rates of glucose production and lipolysis were analyzed by gas chromatography-mass spectrometry following constant rate infusion of [6,6-(2)H2]glucose and [2-(13)C]glycerol. Insulin sensitivity was assessed by the Homeostasis Assessment Model. In 8 of the infants, the effect of an intravenous injection of 0.2 mg/kg glucagon was also analyzed. RESULTS: Plasma glucose and glycerol averaged 3.8 +/- 0.5 mmol/L and 384 +/- 183 micromol/L, respectively. The glycerol production rate, reflecting lipolysis, was 12.7 +/- 2.9 micromol/kg per min. Mean rate of glucose production was 30.2 +/- 4.6 micromol/kg per min. Homeostasis Assessment Model insulin sensitivity corresponded to 82% +/- 19%, beta-cell function to 221% +/- 73%, and insulin resistance to 1.3 +/- 0.3. After glucagon administration, rate of glucose production increased by 13.3 +/- 8.3 micromol/kg per min and blood glucose by 1.4 +/- 0.5 mmol/L. Glycerol production decreased from 12.8 +/- 3.0 to 10.7 +/- 2.9 micromol/kg per min. Mean insulin concentration increased from 10.9 +/- 3.0 to 30.9 +/- 10.3 mU/L. There was a strong inverse correlation between the decrease in lipolysis and increase in insulin after glucagon administration. CONCLUSIONS: Infants who are born large for gestational age show increased lipolysis and a propensity for decreased insulin sensitivity already at birth. The simultaneous increase in plasma insulin correlated strongly with the noted decrease in lipolysis, indicating an antilipolytic effect of insulin in these infants.

Energy substrate production in infants born small for gestational age.

AIM: To investigate energy substrate production and its hormonal regulation in infants born small for gestational age. METHODS: Eleven infants, aged 24.4 +/- 5.3 hour, were studied following a fast of 4.0 +/- 0.6 hour. Gestational age was 35.4 +/- 2.8 weeks and birth weight 1804 +/- 472 g (<-2 SD). Rates of glucose production and lipolysis were analyzed using [6,6-(2)H(2)]-glucose and [2-(13)C]-glycerol. RESULTS: Plasma levels of glucose and glycerol were 4.1 +/- 1.1 mmol x L(-1) and 224 +/- 79 micromol x L(-1), respectively. Glucose appearance averaged 30.3 +/- 8.2 and glucose production rate 21.1 +/- 6.1 micromol x kg(-1) x minutes(-1). Glycerol production rate was 5.6 +/- 1.6 micromol x kg(-1) x minutes(-1), correlating strongly to birth weight (r = 0.904, p < 0.001). Of the glycerol produced, 55 +/- 22% was converted to glucose, corresponding to 8 +/- 3% of the glucose production. CONCLUSIONS: Even though the infants could produce energy substrates, lipolysis was reduced and the glucose production was in the low end of the normal range compared with infants born appropriate for gestational age. The correlation between glycerol production and birth weight indicates that lipolysis depends on the amount of stored fat. Data on insulin and insulin-like growth factor binding protein 1 support the view that insulin sensitivity in these infants is reduced in the liver but increased peripherally.

Increased lipolysis in non-obese pregnant women studied in the third trimester.

BACKGROUND: During pregnancy, metabolic adaptation takes place in the mother to provide for the supply of substrates to the growing fetus. OBJECTIVE: To determine rates and endocrine regulation of lipolysis and glucose production (GPR) in late pregnancy. DESIGN: Energy substrate production was measured in healthy pregnant women by use of stable isotope-labelled compounds. SETTING: University Hospital, Uppsala, Sweden. SAMPLE: Eight healthy non-obese, non-smoking women with normal pregnancies were studied at 33-36 weeks of gestation after an overnight (12-14 hours) fast. METHODS: Rates of glycerol and glucose production were analysed by gas chromatography/mass spectrometry following constant rate infusion of [1,1,2,3,3-(2)H(5)]-glycerol and [6,6-(2)H(2)]-glucose. MAIN OUTCOME MEASURE: Glycerol and glucose production in the third trimester. RESULTS: The mean rate of glycerol production, reflecting lipolysis, was 3.06 (0.66) and the mean GPR was 13.2 (1.5) micromol kg(-1) minute(-1) [2.38 (0.27) mg kg(-1) minute(-1)]. There was a correlation between rate of glycerol production and GPR (r = 0.75, P = 0.033). Fasting insulin levels correlated inversely with both the rate of glycerol production (r = -0.85, P = 0.008) and GPR (r = -0.78, P= 0.021). CONCLUSIONS: Our results show that lipolysis is markedly increased during late pregnancy compared with reported data for non-pregnant women. The data also confirm the occurrence of an increased GPR in pregnant women. The finding of a correlation between rate of glycerol production and GPR corroborates the view that lipolysis promotes gluconeogenesis. Although late gestation is associated with insulin resistance, the results show that insulin plays a regulatory role both in lipolysis and glucose production.