The editorial on glucose and small for gestational age infants(1) suggested that "the frequency of hypoglycemia in the SGA infants, and its occurrence in relation to postnatal age remains unknown". Also, on the basis of earlier work conducted in well-nourished populations in the USA and Europe, they considered whether or not SGA infants have a normal capacity for gluconeogenesis, and adequate supplies of alternative fuels like ketone bodies and lactate.

We would like to draw attention to two papers published this month(2,3) which have examined the prevalence and risk factors for neonatal hypoglycemia, and the levels of alternative fuels, in a large population of newborn infants in Kathmandu, Nepal where rates of intrauterine growth retardation, as in India, are high.

1. Neonatal hypoglycemia was more common in this developing country setting (41% with mild and 11% with moderate hypogly-cemia), but may not be a clinical problem unless all fuel availability is reduced.

2. Some "textbook" risk factors, like hypo-thermia, disappeared after controlling for confounding variables. The risk of moderate hypoglycemia was high in the second 12 hours of life for babies with delayed onset of feeding, highlighting the importance of promotion of early feeding. Raised maternal TSH and maternal anemia emerged as prenatal risk factors.

3. Alternative fuels are important in the metabolic assessment of neonates, and they might provide effective cerebral metabolism even during moderate hypoglycemia. Hypoglycemic infants generally had lower levels of alternative fuels through either reduced availability or increased consump-tion.

4. Low birth weight and SGA infants had higher ketone body levels than normal birth weight infants when glucose levels were low, suggesting that nutritionally compro-mised and SGA infants do exhibit increased counter-regulatory ketogenesis. Hypo-thermia, male gender and low infant T4 were associated with impaired counter-regulation after birth.

We hope this research stimulates other studies in India on this important aspect of neonatal nutrition.

Anthony Costello,
Institute of Child Health, 30 Guilford St, London WC1N1EH, UK,

Dharma Manandhar,
Executive President, MIRA, GPO Box 921, Kathmandu, Nepal.

1. Kalhan S, Alur P. Glucose and small for gestational age infants. Indian Pediatr 1999; 36: 1205-1209.

2. Pal DK, Manandhar DS, Rajbhandari S, Land JM, Patel N, Costello AM de L. Neonatal hypoglycemia in Nepal. 1. Prevalence and risk factors. Arch Dis Child 2000; 82; F46-F51.

3. Costello AM de L, Pal DK, Manandhar DS, Rajbhandari S, Land JM, Patel N. Neonatal hypoglycemia in Nepal. 2. The role of alternative fuels. Arch Dis Child 2000; 82; F52-F58.

 

Drs. Costello and Manandhar have cited the editorial on glucose and small for gestatioanl age infants out of context. We had suggested that, based upon published data, it is difficult to estimate the frequency of hypoglycemia in SGA infants in relation to present clinical practice. In addition, we cited publications to show that SGA infants have a normal capacity for gluconeogenesis and ketogenesis.

The two publications from their group on infants in Nepal are extremely important and provide very useful data. However, they should be examined in the context of not only maternal nutrition, but also in relation to clinical practice. As reported, the data were obtained in exclusively breast-fed infants. A large number of infants (58% under 6 h of age and 37% from 6 to 12 h of age) were not fed. The authors defined mild hypoglycemia as glucose <2.5 mmol/L and severe as <2.0 mmol/L. Data from other studies in European countries show that exclusively breast-fed infants maintain lower plasma glucose concentrations than formula fed infants. In fact, in the study by Swenne et al.(1), almost 50% of the infants had plasma glucose concentrations less than 2 mmol/L in the first 48 h after birth. Similar data were reported by Hawdon et al.(2). In this context, the maternal malnutrition and SGA in the studies from Nepal may not have added additional risk for hypoglycemia. Caution should be exercised in the interpretation of alternate fuel data because their levels are easily influenced by exogenous nutrient supply (i.e., feeding), rather than endogenous reserves. Higher ketone body levels are not unusual in breast-fed infants while the feeding patterns are being established. Since TSH is an important regulator of lipolysis in the neonate, the finding of low ketone bodies with lower T4 levels in infants is not surprising(3).

Nonetheless, the studies of Pal et al. and Costello et al. are two very important contributions which provide new data on glucose and other metabolic fuels in normal and low birth weight infants in a developing country(4,5).

1. Swenne I, Ewald U, GustafssonJ, Sandberg F, Ostenson C. Inter-relationship between serum concentrations of glucose, glucagon and insulin during the first two days of life in healthy newborns. Acta Pediatr 1994; 83: 915-919.

2. Hawdon JM, Ward Platt MP, Aynsley-Green A. Patterns of metabolic adaptation for preterm and term infants in the first neonatal week. Arch Dis Child 1992; 67: 357-365.

3. Marcus C, Ehren H, Bolme P, Arner P. Regulation of lipolysis during the neonatal period. J Clin Invest 1988; 82: 1793-1979.

4. Pal DK, Manandhar DS, Rajbhandari S, Land JM, Patel N, Costello AM. Neonatal hypo-glycemia in Nepal. 1. Prevalence and risk factors. Arch Dis Child 2000; 82: F46-F51.

5. Costello AM, Pal DK, Manandhar DS, Rajbhandari S, Land JM, Patel N. Neonatal hypoglycemia in Nepal. 2. The role of alternative fuels. Arch Dis Child 2000; 82: F52-F58.