Year : 2012 | Volume
: 1 | Issue : 2 | Page : 90--93
Study of pattern of blood sugar levels in low birth weight babies who are exclusively on breast milk
VSS Yerramilli Murty, Kethireddi Dinendra Ram
Department of Pediatrics, Maharajah's Institute of Medical Sciences, Nellimerla, Vizianagaram Dt, Andhra Pradesh, India
VSS Yerramilli Murty
Quarter No B2, MIMS Campus, Maharajah«SQ»s Institute of Medical Sciences, Nellimerla Vizianagaram - 535217, Andhra Pradesh
Background: Breast feeding of every newborn baby is being widely advocated in view of its undoubted and multiple benefits to both newborn baby and mother. But low birth weight (LBW) babies with several handicaps may not maintain blood sugar level. Adequacy of breast milk in maintaining euglycemia in LBW newborn babies is being studied.
Aims: To study the pattern of blood sugar levels in LBW babies who feed exclusively on breast milk.
Settings and Design: This is a prospective study conducted in postnatal ward and neonatal intensive care unit of a tertiary care centre. One hundred consecutive neonates with a birth weight less than 2500g when born, being fed exclusively with breast milk were studied.
Materials and Methods: Estimation of blood sugar levels in LBW neonates with birth weight less than 2500g who were given direct breast feeding or expressed breast milk exclusively.
Results: The present study revealed that 95% of LBW neonates maintained adequate blood sugar levels during the first 72 hours of life with breast milk irrespective of gestational age and birth weight studied. Single episode of hypoglycemia occurred in 5% of these LBW babies.
Conclusions: There is a very low incidence of hypoglycemia in LBW newborn babies (including intrauterine growth retardation (IUGR) and preterm babies) on exclusive breast feeds. Breast milk is optimal feed in these LBW babies.
|How to cite this article:|
Murty VY, Ram KD. Study of pattern of blood sugar levels in low birth weight babies who are exclusively on breast milk.J NTR Univ Health Sci 2012;1:90-93
|How to cite this URL:|
Murty VY, Ram KD. Study of pattern of blood sugar levels in low birth weight babies who are exclusively on breast milk. J NTR Univ Health Sci [serial online] 2012 [cited 2020 Feb 22 ];1:90-93
Available from: http://www.jdrntruhs.org/text.asp?2012/1/2/90/98342
The fetus in utero is entirely dependent on the mother for glucose. At the time of birth, the neonate must abruptly switch from having a continuous supply of glucose from maternal blood in fetal life to maintaining its own supply of glucose during periods of fasting, and when feedings are interspersed intermittently. Disturbances of metabolic and endocrine systems may frequently occur in neonates, because of developmental immaturity. The blood sugar values are influenced by birth weight, gestational age, feeding method, and postnatal age. In low birth weight (LBW) babies the liver weight is much reduced, whereas the brain weight remains within normal limits, so that the ratio of brain weight to liver weight is greater than five. This along with several other factors related to intrauterine growth retardation (IUGR) and prematurity, result in hypoglycemia with its potential complications.
Depending upon the gestational maturity and vigor of the child, there may be difficulties in self-feeding. The baby may not be able to suck or there may be in coordination between sucking and swallowing. This study was done to evaluate the incidence of hypoglycemia in LBW neonates who are on exclusive breast feeding. Neonatal hypoglycemia, even if asymptomatic; could lead to long-term adverse neurodevelopmental impairment. In preterm infants with repetitive decrease in glucose level less than 47mg/dl were associated with reduced mental and motor developmental scores and increased neurodevelopmental impairment.
Materials and Methods
This is a prospective study conducted in the postnatal ward and neonatal intensive care unit (NICU) of a tertiary care center, in which 100 consecutive neonates with a birth weight less than 2500g, being fed exclusively with breast milk were studied A total of 100 LBW neonates (70 term IUGR and 30 preterm babies) were included in the study.
All neonates were weighed at birth with an electronic weighing machine with an accuracy of +5g.
LBW neonates with birth weight less than 2500g were given direct breast feeding or expressed breast milk exclusively. They were given exclusive breast feed within half an hour after normal delivery and within one hour after a caesarian delivery. Thereafter breast feed was given at two hourly intervals. They were monitored in NICU/postnatal ward depending upon the clinical status of the neonate and managed as per the standard unit protocol.
Gestational assessment was done by the New Ballard Score. The newborn was classified depending on gestational age and birth weight as follows:
Term-IUGRPreterm-Appropriate for gestational age (AGA)
-Small for gestational age (SGA)
Blood sugar was estimated at 0 h (cord blood), 1, 3, 6, 12, and 24h and 8 th hourly thereafter during the first 3 postnatal days. This was done on capillary blood obtained by heel prick.
Venous sample was sent to laboratory for confirmation if the blood sugar was less than 47 mg/dl.
A blood sugar level less than 47 mg/dl was considered as hypoglycemia.
Symptoms of hypoglycemia if associated were noted.
Neonates were managed as per the standard protocol. Asymptomatic hypoglycemia was first treated by adjusting the enteral feeding regimen. Blood sugar monitoring was done at frequent intervals. If this approach failed, intravenous therapy was instituted.
Exclusion criteria: Neonates born to diabetic mothers, Beckwith-Wiedemann syndrome, maternal tocolytic therapy with beta-sympathomimetic agents, maternal chlorpropamide therapy, thiazide diuretics, and infants given exchange transfusion. Neonates receiving intravenous fluids were not included in study.
Method of estimation of blood sugar
The blood glucose estimation was done with reflectance colorimeter using test strips.
The test strip is a firm plastic strip to which an impregnated reagent is affixed. The blood glucose test is based on measurement of electrical current caused by the reaction of glucose with the reagents on the electrode of the test strip. The blood sample is drawn into the reaction zone of the test strip through capillary action. The sample reacts with glucose oxidase triggering the oxidation of glucose in the blood. Electrons are generated, producing a current that is proportional to the glucose in the sample. After the reaction time, the glucose concentration in the sample is displayed.
Blood sugar levels were studied in 100 LBW (2500g and below) neonates at 0, 1, 3, 6, 12, and 24h of life on the first day and eighth hourly on day two and day three of life.
There were 70 term IUGR neonates and 30 were preterm. All the preterm neonates were AGA and none of them were SGA. Out of the total 100 cases, 56 were female and 44 were male. In the term IUGR neonates, there was a steady increase in the blood sugar levels over the first 3 days of life. In the present study there were four cases of hypoglycemia on the first day of life. Two cases of hypoglycemia occurred at 3 rd hour of life and another at 6 th hour of life and the fourth at 24 hours of life. Laboratory confirmation of the low blood sugar level was made in all the four cases. All the neonates were asymptomatic for hypoglycemia during the first 24 hours of life. Thus the incidence of asymptomatic hypoglycemia in this study was 5.7% in term IUGR babies. There was no case of symptomatic hypoglycemia that occurred in this group in this study. In the preterm group in the present study, mean blood sugar level increase over the first 72 hours was seen. But the increase in blood sugar was not uniformly progressive. In our study, the incidence of hypoglycemia was 3.33% in the preterm group. All the babies in this group were AGA. An analysis of the results obtained in the present study revealed that all LBW neonates maintained adequate blood sugar levels during the first 72 hours of life with breast milk irrespective of gestational age and birth weight studied. Single episode of hypoglycemia occurred in 5% of these LBW babies, which was asymptomatic, thus making blood sugar monitoring essential in LBW babies in the first 24 hours of life.
The term "hypoglycemia" refers to a low blood glucose concentration. Neonatal hypoglycemia is not a medical condition in itself, but a feature of illness or of failure to adapt from the fetal state of continuous transplacental glucose consumption to the extrauterine pattern of intermittent nutrient supply. There is controversy over the definition of a "safe" blood glucose concentration, that is, a value below which there is risk of long-term neurodevelopmental impairment. Hypoglycemia associated with abnormal clinical signs (symptomatic hypoglycemia) has a poor short- and long-term outcome but evidence of risk in the absence of clinical signs (asymptomatic hypoglycemia) is inconclusive.
In the present study, of the 100 neonates who were fed exclusively on breast milk, 70 were IUGR and 30 were preterm. In the term IUGR neonates there was a steady increase in the blood sugar levels over the first 3 days of life. In a study by Sharma et al.,  mean fasting blood sugar level in term SGA neonates was 35.5 + 1.3mg/dl followed by mean blood sugar levels at 2, 12, 24, 36, 48, and 72h being 26.5+ 1.4mg/dl, 29.1+1.1mg/dl, 35.5+2.0mg/ dl, 41.4+2.2mg/dl, 45.9+1.2mg/dl, and 51.1+2.1mg/dl, respectively, thus indicating an uniform increase in blood sugar levels from 2 hours onwards.  A similar pattern of increase in blood sugar was observed in this study but the values of blood sugar are higher than the values obtained in the study by Sharma et al.  In the present study there were four cases of hypoglycemia on first day of life. Two cases of hypoglycemia occurred at 3 rd hour of life and another at 6 th hour of life and the fourth at 24 hours of life. Laboratory confirmation of the low blood sugar level was made in all the four cases. All the neonates were asymptomatic for hypoglycemia during the first 24 hours of life. Thus the incidence of asymptomatic hypoglycemia in this study was 5.7% in term IUGR babies. There was no case of symptomatic hypoglycemia that occurred in this group in this study. In a study by Haltrop, the incidence of hypoglycemia in IUGR babies was 14.7%. This was higher than the incidence noted in this study. 
The incidence of hypoglycemia obtained in our study were higher than the study by Ishikawa, who studied blood sugar values of low grade low birth weight infants (LGLBWI) (2100g < birth weight < 2500g) whose only abnormality is LBW. Whole blood glucose was measured five times (0, 0.5, 1, and 4h after birth, and just before the first bottle feeding) in 49 LGLBWI and 38 normal birth weight infants. No hypoglycemia that required treatment was found among full-term normal LGLBWI, even those who were SGA. Both these studies cannot be compared because Ishikawa studied only on LGLBWI, obtained only five measures of blood sugar and used much lower cut-off values of blood sugar for defining hypoglycemia.  The incidence of hypoglycemia was lower than that obtained in the study by Bhat et al., whose study showed a overall incidence of hypoglycemia of 25.2% in SGA babies. But the timing of incidence was similar to this study where all the episodes of hypoglycemia occurred in the first 24 hours. In study of Bhat et al., 98% of the episodes occurred within the first 24 hours. 
In the preterm group in the present study, mean blood sugar level increase over the first 72 hours was seen. But the increase in blood sugar was not uniformly progressive. This corresponds to the findings of Haworth and Ford, who studied the effects of early and late feeding upon blood sugar levels in preterm babies. In a group of 15 babies with mean birth weight of 1869g and mean gestational age of 35 weeks who belonged to early fed group, the mean blood sugar levels were 24.4+10.1mg/dl, 40.9+21.9mg/dl, and 27.5+22.6mg/dl on day 1, 39+13.7mg/dl, 37.5+8.6mg/dl, and 54+18.8mg/dl on day 2, and 32.5+15.8mg/dl, 42.2+16.3mg/dl, and 42.1+11.5mg/dl on day 3. However, blood sugar values below 20mg/dl were found in six babies and below 10mg/dl in three babies though none of the babies exhibited signs of hypoglycemia. This is in contrast to our study where none of the neonates in preterm group was observed to have blood sugar levels below 20mg/dl. In India Karan et al., compared blood sugar levels in LBW (weighing less than 2500g) in early fed group and starved group. There were 147 babies in the starved group and 13 of these had blood sugar levels less than 20mg/dl, whereas, none of the 64 infants who were fed had a blood glucose less than 20mg/dl. 
In our study, the incidence of hypoglycemia was 3.33% in the preterm group. All the babies in this group were AGA. In 1968, Raivio and Hallman reported a frequency of 1.4% of hypoglycemia in these infants.  Fluge reported that as many as 14% of AGA infants showed evidence of neonatal hypoglycemia. 
In the present study an analysis of preterm neonates based on gestational age revealed that only at gestational age of 36-37 weeks, there was an uniform increase in blood sugar levels over the first 72 hours of life. This group resembled term IUGR babies in having a uniform increase in blood sugar levels over the first 72 hours. This could be related to increase maturity of endocrine system with increase in gestational age and hence relatively better glucoregulatory mechanism.
In our study there were five LBW babies in preterm and IUGR groups who had blood sugar levels below 47mg/dl. All these cases of hypoglycemia occurred within the first 24 hours of life. The incidence of hypoglycemia was more common in the first 24 hours of life. This is similar to the study by Karahasanoglu et al. In this prospective study, he investigated the frequency of hypoglycemia and the proper intervals for screening in SGA neonates. They noted that the frequency of hypoglycemia in SGA neonates was significantly higher (p:0097) than in AGA neonates. The first 3 hours, the 6 th hour and the 48 th hour postnatally were the most common hours for encountering hypoglycemia. They concluded that clinical signs were not true indicators of hypoglycemia. The first 3 hours, the 6 th hour and the 48 th hour postnatally were the most common hours for encountering hypoglycemia in their study.  These data suggest that screening for hypoglycemia in SGA neonates should continue for 48 hours.
An analysis of the results obtained in the present study revealed that all LBW neonates maintained adequate blood sugar levels during the first 72 hours of life with breast milk irrespective of gestational age and birth weight studied. Single episode of hypoglycemia occurred in 5% of these LBW babies, which was asymptomatic thus making blood sugar monitoring essential in low birth weight babies.
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