Indian Pediatrics 1999; 36:296-300
Growth and Morbidity Patterns of Exclusively Breast-fed Pre term Babies
Low birth weight (LBW) infants run a higher risk of mortality and morbidity(1). The aim of adequate nutrition in preterm infants is not only satisfactory weight gain but also a decrease in morbidity and mortality rates(2). Optimal nutritional management of these infants aims at achieving a rate of growth equal to the intrauterine rate(3).
Human milk was considered to be inadequate for the growth of preterm infants inspite of its numerous advantages(4-6). The demonstration of higher protein and mineral content in the milk produced by mothers of preterm infants has revived interest in human milk for this valuable group of infants(7-9). Given the economic advantages, metabolic efficiency, immunological benefit and demonstration of higher protein and mineral content in the milk produced by mothers of preterm infants, breastfeeding from their own mothers appears to be the best option for these infants( 10).
A reasonably good determinant of adequacy of breast milk is longitudinal observation of the infants growth. There are few studies on growth and morbidity patterns of preterm babies in relation to feeding practices. The present study was therefore undertaken to find out the growth and morbidity patterns of exclusively breast fed preterm babies in comparison to mixed fed preterm infants.
Subjects and Methods
A total of fifty preterm babies with birth weight of 1200 g to 2000 g and gestational age 32-36 weeks constituted material of the present study. The exclusion criteria were severe birth asphyxia, respiratory distress, major congenital anomalies, those requiring intensive care and those who had received TPN. These babies were excluded as they required various interventions during stabilization and feeding was delayed for a longer time.
In our routine practice, all the newborns receive exclusive breastfeeding either directly form the breast or feeding of expressed breast milk with spoon and katori. However, some of the babies occasionally received supplementary feeding due to lower yield or unavailability of expressed breast milk. Babies were thus divided into 2 groups according to feeding practices.
Group I [Exclusively breast fed group (EBF)]: A total of 56 babies were enrolled in group I out of which 23 babies were excluded due to introduction of Supplementary feeding in form of formula after initial exclusive breast feeding for 4 to 6 weeks. Five babies were lost during follow up period due to transfer and shift of parents and 3 babies who missed more than 2 follow up visits were also excluded. Twenty five preterm babies who received only breast milk till 4th month of postnatal age thus constituted the material for group I.
Group II[Mixed fed group (MF)]: A total of 33 babies were enrolled in group II out of which 6 were lost due to transfer of parents and 2 were excluded because they missed 2 follow up visits in spite of best efforts to contact them. Twenty five preterm babies who received predominantly supplementary feeding in the form of home available milk without dilution constituted material for group II. The supplementation was started after initial stabilization at the age of 4-14 days with a mean duration of 8.4 days. These babies continued to be on supplementary feeds till the end of follow up period.
All these babies were followed up from birth to 4th month of postnatal age at an interval of 15± 5 days in the Well Baby Clinic. Babies were followed up till the 4th month of postnatal age due to the fact that complementary foods are usually introduced after 4th month. During each follow up visit, growth pattern was recorded by measuring weight, head circumference, chest circumference and length. All measurements were done by standard techniques(11) by a single observer (PK). Data entry was done by another observer.
All the mothers were sensitized to maintain records regarding sickness episodes and at each follow up visit detailed history was taken regarding any episode of illness during the interval between 2 visits: A morbidity for the present study was defined as "Any episode in which there was an evident alteration in the infant well being and activity as noticed by the mother, substantiated whenever possible by dispensary, OPD and/or hospital slips and by clinical examinations of the child". Hospitalizations were recorded and details of hospitalized babies were evaluated.
The results were fed into a computer software "STATISTIX". Data was analyzed by using ANOVA. Student 't' test was applied to compare individual growth data of both groups at different postnatal ages.
The mean birth weight of group I was 1556 (±166) g and the mean gestational age 33.84 weeks. The mean birth weight of group II was 1555 (± 196) g and gestational age 33.72 weeks. Both the groups were comparable for birth weight and gestation. The groups were also matched for socioeconomic status, maternal education, parity, nuclear or joint family and sex distribution. The mean weight of group I was significantly higher than group II from 2nd month to the end of 4th month of followup period. Group I babies gained 380.2 g, 940.6 g, 833 g and 668 g in 0-1 month, 1-2 month, 2-3 month, 3-4 month intervals respectively as compared to 314.2 g, 657.2 g, 704 g and 610 g in Group II (Table I).
As depicted in Table I, head and chest circumferences were significantly higher in group I till 4th month of postnatal age. No significant difference in length was observed between groups I and II during 4 months of follow up period (Table I). ANOVA for anthropometry revealed significant differences both within and between groups for weight, head and chest circumference but not for length.
Morbidity was higher in group II, i.e., mixed fed babies. Group I had 40 sickness episodes/100 children months as compared to 69/100 children months in group II. Diarrheal episodes were 20/100 children months in group II as compared to 6/1 00 children month in group I (p <0.01). Pneumonia, otitis media and hospitalization all were higher in group II (Table II); Six babies in group I and 4 babies in group II did not have even one episode of illness. No baby in either group had more than 4 episodes of sickness during follow up.
In the present study it was observed that exclusively. breast fed preterm babies regained birth weight at 2 weeks and then gained 338 g in next two weeks which is near intrauterine growth rate. The mean weight of group I, i.e., EBF group was significantly higher from 2nd month onwards till the of follow up period. Group I babies also had greater head and chest circumferences than group II babies. However, there was no significant difference in linear growth. These results challenge the myth that preterm babies require supplementary feeding. Earlier studies reported that preterm infants fed pooled or preterm breast milk without fortification grew less well(l2,13). However, the babies included in these two studies were extremely low birth weight with an average birth weight of 1238 g and mean gestational age of 31.6 weeks. It may therefore be reasonable to postulate that babies around 33-34 weeks of gestational age can be well managed on exclusive breast feeds but the same may not be true for extremely preterm babies.
It was further observed that sickness episodes were significantly lower in exclusively breast fed preterm babies. Diarrhea, DRI, Pneumonia and hospitalization all were lower in exclusively breast fed group. However, the overall sickness episodes reported in the present study is less than in earlier studies(14,15). This may have resulted from health education imparted to all mothers during each follow up visit and remedial measures like discouraging bottle feeds.