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J E Harding

Publications and source records attributed to J E Harding.

At least 37 records · Page 2Linked to original sources
PubMed2001

Calcium and phosphorus supplementation of human milk for preterm infants.

BACKGROUND: Preterm infants are born with low skeletal stores of calcium and phosphorus. Preterm human milk provides insufficient calcium and phosphorus to meet their estimated needs. OBJECTIVES: To determine if addition of calcium and phosphorus supplements to human milk leads to improved growth and bone metabolism without significant adverse effects in preterm infants. SEARCH STRATEGY: The standard search strategy of the Cochrane Neonatal Review Group (NRG) was used. This includes searches of the Oxford Database of Perinatal Trials, MEDLINE, previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants, journal handsearching mainly in the English language. SELECTION CRITERIA: All trials utilizing random or quasi-random allocation to supplementation of human milk with calcium and/or phosphorus or no supplementation in preterm infants within a hospital were eligible. DATA COLLECTION AND ANALYSIS: Data were extracted using the standard methods of the Cochrane NRG, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk and weighted mean difference. MAIN RESULTS: No studies which met selection criteria were identified. Excluded studies that were identified included minerals as one component of a multicomponent fortifier or reported only non-clinical outcomes (for example, urinary excretion of calcium). Two studies were excluded because of methodological concerns. REVIEWER'S CONCLUSIONS: There are no randomized controlled data evaluating clinical outcomes of calcium and phosphorus supplementation of human milk for preterm infants on which to base practice recommendations. Further trials should assess the clinical benefits and potential adverse effects of supplementation of human milk with minerals. This may best be done in the context of manipulation of the composition of human milk fortifiers containing multiple nutrients (carbohydrate, protein, and minerals).

Calcium↗
PubMed2001

Early chest radiographs in very low birth weight babies receiving corticosteroids for lung disease.

We set out to determine whether chest radiographs obtained in premature infants between 9-16 days of age are predictive for the development of chronic lung disease of the newborn (CLD). This was a prospective cohort study. The study included 40 babies who were enrolled in a randomized trial of corticosteroid therapy for the prevention of CLD. Chest radiographs were obtained for clinical indications between 9-16 and 25-35 days of age. All chest radiographs were assessed by a single pediatric radiologist who was unaware of the treatment allocation and who used a previously published scoring system devised by Weinstein et al. [Pediatr Pulmonol 1994;18:284-289]. The radiographic score at 9-16 days correlated well with the radiographic score at 25-35 days of age (correlation coefficient, 0.69, P < or = 0.001). The scores at 9-16 days were significantly higher in those babies who had CLD at 28 days postnatal age (PNA) (P = 0.03) and at 36 weeks postmenstrual age (PMA) (P = 0.002). Using a receiver-operator characteristic curve, we have determined that for a radiographic score of 3 or greater at 9-16 days, the sensitivity for CLD was 0.64, and specificity was 0.84. We conclude that a chest radiograph taken between 9-16 days may help predict which at-risk preterm infants will develop CLD.

Adrenal Cortex Hormones↗
PubMed2001

Growth restriction in dexamethasone-treated preterm infants may be mediated by reduced IGF-I and IGFBP-3 plasma concentrations.

OBJECTIVE: Preterm infants receiving dexamethasone for respiratory morbidity frequently suffer restricted growth. The aim of this study was to investigate the interactions between dexamethasone treatment regimen and circulating IGFBP-3 and IGF-I levels, and the associations between these variables and linear growth rate in preterm babies receiving dexamethasone for chronic lung disease of prematurity. DESIGN: A randomised, unblinded, clinical trial of two different courses of dexamethasone: a 42-day tapering course (the long course) and a repeatable 3 day pulse course. PATIENTS: Forty preterm infants (19 in the pulse group, 21 in the long group) with a birthweight < or = 1250 g who were ventilated at 7 days of age. MEASUREMENTS: Lower leg length was measured thrice weekly by knemometry, and IGFBP-3 and IGF-I levels were measured prior to commencing treatment, at 14 and 42 days of treatment and at 36 weeks postmenstrual age (PMA). Interactions between variables were analysed by stepwise regression analysis and analysis of covariance (ANCOVA). Associations between variables were assessed by correlation coefficients. RESULTS: In an ANCOVA, mean daily dose of dexamethasone/kg (MDDD) and treatment group both significantly influenced IGFBP-3 levels (P = 0.0009 and P = 0.017, respectively), and tended to influence IGF-I levels similarly (P = 0.098 and P = 0.07). MDDD also significantly influenced mean daily increase in lower leg length (MDILL; P < 0.01). IGFBP-3 and IGF-I levels were significantly related to MDILL (ANCOVA: P < 0.01). The correlation coefficients for IGFBP-3 and IGF-I levels and MDILL were 0.2 and 0.3 (both P < 0.0001), respectively. IGFBP-3 and IGF-I levels were highly correlated (r(2) = 0.52, P < 0.0001) and both increased significantly with increasing PMA (P < 0.0001). IGF-I levels were higher in females (P = 0.036). CONCLUSION: This study provides evidence that the growth-restricting effects of dexamethasone may be mediated, at least in part, via suppression of the IGF axis. Both dexamethasone dose and treatment regimen influence circulating IGF-I and IGFBP-3 levels, and both are important in inducing growth restriction.

Analysis of Variance↗
PubMed2001

Chest physiotherapy and porencephalic brain lesions in very preterm infants.

OBJECTIVE: National Women's Hospital is one of two hospitals to report a destructive brain lesion, namely encephaloclastic porencephaly (ECPE), in extremely preterm infants. It has been associated with non-cephalic presentation, early hypotension and the number of chest physiotherapy treatments in the first month. The aim of the present study was to determine the temporal relationship between ECPE and chest physiotherapy use in very low-birth weight (VLBW) infants in our unit. METHODOLOGY: Cerebral ultrasound scan reports, post-mortem reports, clinical and physiotherapy records and, if indicated, original ultrasound films were reviewed for all VLBW babies admitted between 1985 and 1998. RESULTS: Over the 14 year period in question, 2219 babies with a birth weight < or = 1500 g were admitted. Encephaloclastic porencephaly was found in only the 13 previously reported babies born between 1992 and 1994. Encephaloclastic porencephaly was excluded in 1564 (70%) babies. In 621 (28%) babies who did not have late ultrasound scans, ECPE was thought to be unlikely either because the babies never had any chest physiotherapy (n=479) or because they had chest physiotherapy but were known to be neurodevelopmentally normal on follow up (n=142). Data were incomplete for 21 babies (0.9%). The number of chest physiotherapy treatments per baby decreased from a median of 95 prior to 1989 to 38 and the age of starting treatment increased from 5 to 8 days after 1990. The use of chest physiotherapy ceased in 1995. CONCLUSIONS: Encephaloclastic porencephaly emerged as a problem at a time when the use of chest physiotherapy had decreased. The cluster of cases seen between 1992 and 1994, although associated with the number of chest physiotherapy treatments given, began to appear because of some other factor.

Analysis of Variance↗
PubMed2001

Do antenatal corticosteroids help in the setting of preterm rupture of membranes?

OBJECTIVE: It is now accepted that corticosteroid administration before preterm delivery reduces neonatal mortality and morbidity. However, corticosteroid use in the setting of rupture of membranes remains controversial. STUDY DESIGN: We reviewed data from the first and largest randomized trial in this area and included them in a new meta-analysis. RESULTS: Data from 318 women with rupture of membranes in the Auckland Trial showed that there was a trend toward reduction of the risk of respiratory distress syndrome with corticosteroids but that this trend did not reach statistical significance. There was little effect on the risks of neonatal death, intraventricular hemorrhage, and fetal, neonatal, or maternal infection. Combined data from 15 controlled trials involving >1400 women with rupture of membranes confirmed that corticosteroids reduce the risks of respiratory distress syndrome (relative risk, 0.56; 95% confidence interval, 0.46-0.70), intraventricular hemorrhage (relative risk, 0.47; 95% confidence interval, 0.31-0.70), and necrotizing enterocolitis (relative risk, 0.21; 95% confidence interval, 0.05-0.82). They also may reduce the risk of neonatal death (relative risk, 0.68; 95% confidence interval, 0.43-1.07). They do not appear to increase the risk of infection in either mother (relative risk, 0.86; 95% confidence interval, 0.61-1.20) or baby (relative risk, 1.05; 95% confidence interval, 0.66-1.68). The duration of rupture of membranes does not alter these outcomes. CONCLUSION: The available data indicate that corticosteroid administration is beneficial in the setting of rupture of membranes. In our opinion further trials to address this question cannot be justified.

Adrenal Cortex Hormones↗
PubMed2001

Abnormal uterine artery Doppler in small-for-gestational-age pregnancies is associated with later hypertension.

In a cohort of normotensive small-for-gestational-age (SGA) pregnancies, we aimed to determine the prevalence of later preeclampsia and gestational hypertension. We hypothesised that (i) uterine artery Doppler abnormalities would increase in severity from those with normotension to gestational hypertension to preeclampsia and (ii) the severity of uterine artery Doppler abnormalities would be related to the severity of fetal disease. Serial uterine and umbilical artery Doppler studies were performed on 224 normotensive women with SGA pregnancies, from detection of SGA until delivery. Outcomes were compared between groups that remained normotensive (n = 174) and those that developed gestational hypertension and preeclampsia. Of the women studied, 50 (22%) subsequently developed hypertension [(3% (n = 8) preeclampsia, 19% (n = 42) gestational hypertension)] at a median (interquartile range) of 19 (12-32) days after recognition of SGA. Mean uterine artery resistance indices (RI) increased from women who remained normotensive (n = 174) to those who later developed gestational hypertension or preeclampsia [0.51 (SD 0.09), 0.55 (0.09), 0.62 (0.13), p < 0.001], as did the proportion of abnormal uterine RI (33%, 39%, 88%, p = 0.007) and umbilical RI (28%, 40%, 75% p = 0.007). Mean uterine RI correlated negatively with z score birthweight (R2 = 0.069, p < 0.001) and positively with umbilical RI (R2 = 0.16, p < 0.001).

Adult↗
PubMed2001

Maternal undernutrition during the periconceptual period increases plasma taurine levels and insulin response to glucose but not arginine in the late gestational fetal sheep.

Maternal undernutrition throughout gestation impairs pancreatic function in the offspring. The influence of periconceptual maternal undernutrition on fetal insulin responses to secretogues in late gestation is unknown. Romney ewes were fed concentrates at 1-2% of body weight/d (UN) or 3-4% of body weight/d (N) from -61 d to +30 d from mating. From 30 d gestation all ewes were fed at 3-4% of body weight/d. At 119 d gestation singleton fetuses (UN; n = 12, N; n = 10) underwent intravenous glucose (1.5 g) and arginine (300 mg) challenge tests. Paired maternal and fetal blood samples were collected over 60 min. Fetal plasma insulin area under the curve (AUC) was larger in UN than in N fetuses during glucose challenge (4.5 +/- 0.6 vs. 2.9 +/- 0.5 nM, p < 0.05) but was not different during arginine challenge. Maternal and fetal plasma taurine concentrations were higher in UN than N (maternal; 110 +/- 11 vs. 75 +/- 8 microM, fetal; 99 +/- 13 vs. 56 +/- 5 microM, both p < 0.05). Maternal periconceptual undernutrition influences fetal insulin secretion without affecting fetal size. The larger plasma insulin responses in UN fetuses could reflect accelerated maturation of pancreatic beta cells or an alteration of other mechanisms regulating insulin secretion. The role of taurine in fetal pancreatic beta cell development requires further investigation.

Animals↗
PubMed2001

The use of renal Doppler ultrasonography to diagnose patent ductus arteriosus in preterm infants.

OBJECTIVE: To prospectively study the diagnostic usefulness of altered renal waveforms in patent ductus arteriosus. METHODS: We studied preterm infants undergoing echocardiography for a suspected patent ductus arteriosus. A spectral Doppler display was acquired for both renal arteries, and a resistive index was obtained. Sensitivity, specificity, and likelihood ratios were calculated using a clinically significant patent ductus arteriosus (>1.5-mm diameter on color Doppler ultrasonography) as the standard of reference. RESULTS: Fifty infants had 78 scans. A significant patent ductus arteriosus was present on 39 scans. When the renal resistive index was greater than 1.0, the likelihood ratio for a significant patent ductus arteriosus was 24.8 (specificity, 97.2%; SD, 3.8%). When the renal resistive index was 1.0 or less, the likelihood ratio for a significant patent ductus arteriosus was 0.2 (sensitivity, 77.2%; SD, 9.4%). CONCLUSIONS: Renal resistive index measurement is a simple investigation that can predict a significant patent ductus arteriosus in patients without congenital heart disease or other causes of diastolic runoff when echocardiography is unavailable.

Ductus Arteriosus, Patent↗
PubMed2000

Carbohydrate supplementation of human milk to promote growth in preterm infants.

BACKGROUND: This section is under preparation and will be included in the next issue. OBJECTIVES: The main objective was to determine if addition of carbohydrate supplements to human milk leads to improved growth and neurodevelopmental outcomes without significant adverse effects in preterm infants. SEARCH STRATEGY: The standard search strategy of the Neonatal Review Group was used. This includes searches of the Oxford Database of Perinatal Trials, MEDLINE, previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants, journal handsearching mainly in the English language. SELECTION CRITERIA: All trials utilising random or quasi-random allocation evaluating the supplementation of human milk with carbohydrate in preterm infants within a nursery setting were eligible. DATA COLLECTION AND ANALYSIS: Not applicable. MAIN RESULTS: No eligible trials were found. REVIEWER'S CONCLUSIONS: There are no studies which have specifically evaluated the addition of carbohydrate alone for the purpose of improving growth and neurodevelopmental outcomes. No recommendations for practice can be made. Research should be directed towards comparison of different quantities and types of carbohydrate in multicomponent fortifiers containing protein and minerals, specifically evaluating short-term growth and long-term growth and neurodevelopmental outcomes.

Dietary Carbohydrates↗
PubMed2000

Fat supplementation of human milk for promoting growth in preterm infants.

BACKGROUND: For term infants, human milk provides adequate nutrition to facilitate growth, as well as potential beneficial effects on immunity and the maternal-infant emotional state. However, the role of human milk in premature infants is less well defined as it contains insufficient quantities of some nutrients to meet the estimated needs of the infant. There are potential short term and long term benefits from human milk, although observational studies have suggested that infants fed formula have a higher rate of growth than infants who are breast fed. OBJECTIVES: The main objective is to determine if addition of supplemental fat to human milk leads to improved growth and neurodevelopmental outcomes without significant adverse effects in preterm infants. SEARCH STRATEGY: The standard search strategy of the Cochrane Neonatal Collaborative Review Group was used. This includes searches of the Oxford Database of Perinatal Trials, MEDLINE, previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants, journal handsearching mainly in the English language. SELECTION CRITERIA: All trials utilizing random or quasi-random allocation to supplementation of human milk with fat or no supplementation in preterm infants within a hospital were eligible. DATA COLLECTION AND ANALYSIS: Data were extracted using the standard methods of the Cochrane Neonatal Collaborative Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk and weighted mean difference. MAIN RESULTS: Results are available for only one small study evaluating the effects of fat supplementation. There are insufficient data to evaluate short term or long term growth outcomes and neurodevelopmental outcomes. There are insufficient data to comment on potential adverse effects. REVIEWER'S CONCLUSIONS: There is insufficient evidence to make recommendations for practice. Further research should evaluate the practice of supplementation of human milk with fat. This may best be done in the context of the development of multicomponent fortifiers. Both short term growth outcomes and long term growth and neurodevelopmental outcomes should be evaluated. Adverse effects should be evaluated.

Dietary Fats↗
PubMed2000

Multicomponent fortified human milk for promoting growth in preterm infants.

BACKGROUND: For term infants, human milk provides adequate nutrition to facilitate growth, as well as potential beneficial effects on immunity and the maternal-infant emotional state. However, the role of human milk in premature infants is less well defined as it contains insufficient quantities of some nutrients to meet the estimated needs of the infant. There are potential short term and long term benefits from human milk, although observational studies have suggested that infants fed formula have a higher rate of growth than infants who are breast fed. Commercially-produced multicomponent fortifiers provide additional nutrients to human milk (in the form of protein, calcium, phosphate, and carbohydrate, as well as vitamins and trace minerals). OBJECTIVES: The main objective was to determine if addition of multiple dietary supplements to human milk leads to improved growth, bone metabolism and neurodevelopmental outcomes without significant adverse effects in premature infants. SEARCH STRATEGY: The standard search strategy of the Neonatal Review Group was used. This includes searches of the Oxford Database of Perinatal Trials, MEDLINE, previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants, journal handsearching mainly in the English language. SELECTION CRITERIA: All trials utilising random or quasi-random allocation to supplementation of human milk with multiple nutrients or no supplementation in premature infants within a nursery setting were eligible. DATA COLLECTION AND ANALYSIS: Data were extracted using the standard methods of the Cochrane Collaboration and its Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk and weighted mean difference. MAIN RESULTS: Supplementation of human milk with multicomponent fortifiers is associated with short term increases in weight gain, linear and head growth. There is no effect on serum alkaline phosphatase levels. Bone mineral content and nitrogen retention appear to be increased. There are insufficient data to evaluate long term neurodevelopmental and growth outcomes. Adverse effects of fortification do not appear to be significantly increased, although the total number of infants studied and the unavailability of results for some infants randomized and subsequently withdrawn reduces confidence in this conclusion. Blood urea levels are increased and blood pH levels minimally decreased, but the significance of this is uncertain. REVIEWER'S CONCLUSIONS: Multicomponent fortification of human milk is associated with short-term improvements in weight gain, linear and head growth. Despite the absence of evidence of long-term benefit and insufficient evidence to be reassured that there are no deleterious effects, it is unlikely that further studies evaluating fortification of human milk versus no supplementation will be performed. Further research should be directed toward comparisons between different proprietary preparations and evaluating both short-term and long-term outcomes in search of the "optimal" composition of fortifiers.

Food, Fortified↗
PubMed2000

Protein supplementation of human milk for promoting growth in preterm infants.

BACKGROUND: For term infants, human milk provides adequate nutrition to facilitate growth, as well as potential beneficial effects on immunity and the maternal-infant emotional state. However, the role of human milk in preterm infants is less well defined as it contains insufficient quantities of some nutrients to meet the estimated needs of the infant. Preterm infants require higher protein intakes than term infants to attain adequate growth rates, and have relatively higher protein turnover rates. Inadequate protein intakes may be partly responsible for low serum albumin and blood urea concentrations in preterm infants. OBJECTIVES: The main objective was to determine if addition of protein to human milk leads to improved growth and neurodevelopmental outcomes without significant adverse effects in preterm infants. SEARCH STRATEGY: The standard search strategy of the Cochrane Neonatal Review Group was used. This includes searches of the Oxford Database of Perinatal Trials, MEDLINE, previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants, and journal handsearching mainly in the English language. SELECTION CRITERIA: All trials utilizing random or quasi-random allocation to supplementation of human milk with protein or no supplementation in preterm infants who remained in hospital were eligible. DATA COLLECTION AND ANALYSIS: Data were extracting using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk and weighted mean difference. MAIN RESULTS: Protein supplementation of human milk results in increases in short term weight gain (WMD 3.6 g/kg/day, 95% CI 2.4 to 4.8 g/kg/day), linear growth (WMD 0.28 cm/week, 95% CI 0.18 to 0.38 cm/week) and head growth (WMD 0.15 cm/week, 95% CI 0.06 to 0.23 cm/week). There are insufficient data to evaluate long term neurodevelopmental and growth outcomes. There are too few infants studied to be certain that adverse effects of protein supplementation are not increased. Blood urea levels are increased (WMD 1.0 mmol/l, 95% CI 0.8 to 1.2 mmol/l). REVIEWER'S CONCLUSIONS: Protein supplementation of human milk in relatively well preterm infants results in increases in short term weight gain, linear and head growth. Urea levels are increased, which may reflect adequate rather than excessive dietary protein intake. Further research should be directed towards the evaluation of specific levels of protein intake in preterm infants and the clinical effects of supplementation with protein, including long term growth and neurodevelopmental outcomes. This may best be done in the context of refinement of available multicomponent fortifier preparations.

Dietary Proteins↗
PubMed2000

A pilot randomized controlled trial of two regimens of fetal surveillance for small-for-gestational-age fetuses with normal results of umbilical artery doppler velocimetry.

OBJECTIVE: This study was undertaken to determine whether the frequency of fetal surveillance could be safely reduced from twice weekly to fortnightly in the case of small-for-gestational-age fetuses with normal results of umbilical artery Doppler velocimetry studies. STUDY DESIGN: Pregnant women between 24 and 36 weeks' gestation (n = 167) with small-for-gestational-age fetuses and normal results of umbilical artery Doppler velocimetry studies were randomly allocated to undergo twice-weekly or fortnightly fetal surveillance. Statistical analysis was carried out according to intention to treat. RESULTS: Eighty-five women were randomly assigned to undergo twice-weekly fetal surveillance and 82 were randomly assigned to undergo fortnightly fetal surveillance. Those randomly assigned to twice-weekly surveillance were delivered 4 days earlier (264 vs 268 days; P =.04) and were more likely to have labor induced (n = 70, 82%, vs n = 54, 66%; P =.02) than those randomly assigned to fortnightly surveillance. Fifty-four babies (23%) were admitted to the neonatal nursery, but there were no differences in neonatal morbidity between the groups. CONCLUSIONS: Maternal intervention (induction) was more common in the twice-weekly group. No differences in neonatal outcomes were detected. A much larger trial is required to determine the safety and potential benefits of less frequent surveillance of small-for gestational-age fetuses with normal results of umbilical artery Doppler velocimetry studies.

Female↗
PubMed2000

The effect of selenium supplementation on outcome in very low birth weight infants: a randomized controlled trial. The New Zealand Neonatal Study Group.

BACKGROUND: Low selenium (SE) status has been documented in preterm infants and has been suggested to be a risk factor for chronic lung disease. METHODS: A total of 534 infants with birth weight <1500 g were enrolled in 8 New Zealand centers in a double-blind placebo-controlled randomized trial of SE supplementation from week 1 of life until 36 weeks' postmenstrual age or discharge home. Supplemented infants received 7 microg/kg/d of SE when fed parenterally and 5 microg/kg/d when fed orally. Plasma SE and glutathione peroxidase concentrations were measured in mothers after delivery and in infants before randomization and at 28 days and 36 weeks' postmenstrual age. Primary outcome measures were oxygen dependency at 28 days and total days oxygen dependency. RESULTS: No significant differences were seen between the groups with respect to primary or secondary outcome measures, with the exception that fewer supplemented infants had an episode of sepsis after the first week of life (P <.038). Mean plasma SE concentrations were 0.33 micromol/L before randomization in both groups and at 28 days had risen in the supplemented group (0.56 micromol/L) but fallen in the control group (0.29 micromol/L) (P <.0001). There was no association between outcome measures and SE concentrations at 28 days or 36 weeks' postmenstrual age. However, lower maternal and infant prerandomization SE concentrations were associated with increased respiratory morbidity. CONCLUSIONS: Postnatal SE supplementation in very low birth weight infants did not improve neonatal outcome. Further investigation of SE supplementation of mothers from the second half of pregnancy is warranted.

Double-Blind Method↗
PubMed2000

Umbilical artery Doppler studies in small for gestational age babies reflect disease severity.

OBJECTIVES: To determine: 1. whether abnormal umbilical artery Doppler studies were independently associated with newborn morbidity; and 2. whether small for gestational age babies with normal umbilical artery Doppler studies had small mothers and a low rate of newborn malnutrition and morbidity. DESIGN: Prospective observational study. SETTING: National Women's Hospital, a tertiary referral centre, Auckland, New Zealand. POPULATION: One hundred eighty-six women and their small for gestational age babies (birthweight < 10th%) who had been participants in one of two randomised controlled trials of small for gestational age pregnancies between 1993 and 1997. METHODS: Newborn morbidity and morphometry were compared between small for gestational age babies with normal and abnormal umbilical artery Doppler studies (resistance index > 95th%). Maternal demographic characteristics and morbidity were also compared. RESULTS: Compared with small for gestational age babies with normal umbilical artery Doppler studies (n = 109), small for gestational age babies with abnormal umbilical artery Doppler studies (n = 77) were diagnosed earlier in pregnancy as being small for gestational age (30.3 vs 32.9 weeks, P < 0.001), were smaller in all body proportions at birth (median Z score birthweight -1.82 vs -1.70, P = 0.004, Z score length -1.86 vs -1.36, P < 0.0001, Z score head circumference -1.31 vs -0.89, P < 0.0001) and were more likely to experience newborn morbidity. When birthweight and gestation were entered into a logistic regression model, an abnormal umbilical artery Doppler study was not an independent predictor of prolonged newborn nursery admission or hypoglycaemia. Of small for gestational age babies with normal umbilical artery Doppler studies, 53 (49%) had low ponderal indices, 26/98 (26%) were hypoglycaemic and 38 (35%) required admission to the newborn nursery. There was no difference in maternal height, weight and ethnicity between the abnormal and normal umbilical artery Doppler groups. CONCLUSIONS: Abnormal umbilical artery Doppler studies reflect earlier onset and more severe growth restriction and are not independently associated with newborn morbidity. Small for gestational age babies with normal Doppler studies have a high rate of newborn nursery admission and malnutrition at birth and are not all just normal small babies.

Adult↗
PubMed2000

Effect of IGF-I on serine metabolism in fetal sheep.

Acute infusion of IGF-I to the fetus has been shown to inhibit amino acid oxidation and appears to increase fetoplacental amino acid uptake. This study was designed to investigate further the effects of IGF-I on fetal amino acid metabolism. Radiolabeled serine was used to test the hypothesis that fetal IGF-I infusion enhances serine uptake into the fetus and/or placenta and inhibits serine oxidation. Eight fetal sheep were studied at 127 days of gestation before and during a 4-h infusion of IGF-I (50 microg/h per kg). During the infusion there was no change in uptake of serine or its oxidation by fetus or placenta. However, both uptake and oxidation of serine and glycine decreased in the fetal carcass. There was also a decrease in fetal blood serine and glycine concentrations which could indicate a decrease in protein breakdown, although reduced amino acid synthesis cannot be excluded. Thus IGF-I appeared to influence the distribution of these amino acids as oxidative substrates between different fetal tissues. In addition, fetal IGF-I infusion increased the conversion of serine to glycine which is likely to have increased the availability of one-carbon groups for biosynthesis. Our data provide further evidence that IGF-I plays a role in the regulation of fetoplacental amino acid metabolism.

Animals↗
PubMed2000

Exogenous GH infusion to late-gestational fetal sheep does not alter fetal growth and metabolism.

The role of GH in the regulation of fetal growth and metabolism in late gestation is not well defined. The aim of this study was to determine the effects of exogenous GH infusion on fetal growth and feto-placental metabolism in the normally growing late-gestation fetal sheep. Eleven fetuses received pulsatile GH infusion (3.5 mg/day) for 10 days while 12 control fetuses received vehicle. The GH infusion was given as a continuous infusion (2.5 mg/day) plus an additional pulsatile component (30 pulses equivalent to 1 mg/day) designed to mimic the natural pattern of GH secretion. Fetal GH infusion raised the circulating fetal concentrations of GH threefold, but did not change fetal concentrations of IGF-I, IGF-binding protein-3, insulin or ovine placental lactogen. GH-treated fetuses had blood urea concentrations 15% lower than controls (P<0.05) and glucose uptake 18% lower per kg fetal weig! ht (P=0.06). There were no other differences attributable to fetal GH infusion in feto-placental metabolism, placental function or placental blood flow. GH-treated fetuses were larger than controls at postmortem (weight+13%, P<0.01; girth+5%, P<0.01; crown-rump length+3%, P<0.05). However, there were no differences between groups in measures of fetal growth (increment in chest girth and hindlimb length). GH-treated fetuses had heavier mothers and when maternal weight was included as a covariate in the analysis, there was no significant difference between treatment groups that could be attributed to GH treatment. GH infusion to normal fetal sheep does not appear to have a significant effect on feto-placental metabolism or fetal growth.

Animals↗