|Year : 2016 | Volume
| Issue : 4 | Page : 247-253
Evaluation of short-term growth in very low birth weight preterm infants at a tertiary hospital in Cameroon
Evelyn Mungyeh Mah1, Andreas Chiabi1, Adéle Bodieu Chetcha1, Seraphin Nguefack1, Felicite Nguefack Dongmo1, Ekoe Tetanye2, Elie Mbonda1, Fru Angwafo III1
1 Department of Pediatrics, Faculty of Medicine and Biomedical Sciences, Yaounde Gyneco-Obstetric and Pediatric Hospital, University of Yaounde I, Yaounde, Cameroon
2 Department of Pediatrics, Faculty of Medicine and Biomedical Sciences, University of Yaounde I, Yaounde, Cameroon
|Date of Web Publication||16-Nov-2016|
Dr. Evelyn Mungyeh Mah
Department of Pediatrics, Faculty of Medicine and Biomedical Sciences, Yaounde Gyneco-Obstetric and Pediatric Hospital, University of Yaounde I, Yaounde
Source of Support: None, Conflict of Interest: None
Aim: This retrospective cohort study describes the short-term growth of very low birth weight (VLBW), preterm babies. We hypothesized that catch-up with term infants occurs by 6 months of chronologic age. Patients and Methods: A total of 113 VLBW preterm babies were discharged alive from the neonatology unit of the Yaounde Gyneco-Obstetric and Pediatric Hospital. Sixty-six of the infants respected their monthly appointments for at least 6 months and were included in the study. The weight was taken daily, while the length and head circumference were taken weekly during postnatal hospitalization period and monthly after discharge. Results: The median birth weight was 1390 g. The mean daily weight gain from the 2nd week of hospitalization was 17.35 g/kg/day. By the 6th month of life, the weights of all the infants were comparable to term babies. The median length at birth was 40 cm, an average monthly increase of 3 cm/month for females, and 3.43 cm/month for males. Babies with length at birth above the 85th percentile reached the growth corridor of term infants by 6 months of life. The median head circumference at birth was 28 cm. The head increased at a rate of 2.5 cm/month for males and 2 cm/month for females. Only those with a head circumference above the 50th percentiles were comparable to term infants at 6 months. Conclusions: VLBW preterm infants caught up in weight with term infants by 6 months of age. Growth in length and head circumference lagged behind.
Keywords: Cameroon, growth, preterm infants, very low birth weight
|How to cite this article:|
Mah EM, Chiabi A, Chetcha AB, Nguefack S, Dongmo FN, Tetanye E, Mbonda E, Angwafo III F. Evaluation of short-term growth in very low birth weight preterm infants at a tertiary hospital in Cameroon. J Clin Neonatol 2016;5:247-53
|How to cite this URL:|
Mah EM, Chiabi A, Chetcha AB, Nguefack S, Dongmo FN, Tetanye E, Mbonda E, Angwafo III F. Evaluation of short-term growth in very low birth weight preterm infants at a tertiary hospital in Cameroon. J Clin Neonatol [serial online] 2016 [cited 2019 Aug 25];5:247-53. Available from: http://www.jcnonweb.com/text.asp?2016/5/4/247/194170
| Introduction|| |
About 25 million neonates with very low birth weight (VLBW) are born each year, and 90% of these births occur in developing countries. Progress in the care of preterm neonates implies improvements in the survival rates of VLBW infants. Today, practitioners in developed countries are more concerned with the long-term outcome of VLBW children rather than their immediate neonatal survival, which stands at over 90%.,,, In developing countries, these rates remain low.,,
Studies have shown that for preterm neonates, lower birth weight remarkably increases the risks of developing growth failure.,, One of the tools for detecting poor health outcomes in preterm children is the evaluation of their growth from birth. At the Yaounde Gynaeco-Obstetric and Pediatric Hospital (YGOPH), the in-hospital survival rate of VLBW preterm neonates is about 50%. No information is available on the postdischarge outcome and considering the high risk of growth faltering in these infants; we sought in this study to assess the growth of VLBW preterm babies over the first 6 months of life at this health facility, with the hypothesis that these infants enter the growth corridor for term infants after the age of 6 months.
| Patients and Methods|| |
We conducted a descriptive, retrospective, cohort study of the somatic growth of VLBW infants. We recruited all preterm babies with birth weights <1500 g admitted in the neonatology unit of the YGOPH and subsequently discharged between January 01, 2008, and December 31, 2012, and followed up regularly for at least 6 months.
Calculation of sample size
The Cochran formula was used to calculate the sample size. The incidence of VLBW at YGOPH was 5.8% in 2011, and the survival rate was 50%. The margin of error was set at 5%, an alpha value of 0.05 for a calculated minimum sample size of 43 infants.
We included all preterm babies born between January 01, 2008, and December 31, 2012, who had birth weights <1500 g; discharged from the neonatology unit of the YGOPH and followed up monthly till the chronologic age of 6 months. Excluded were all preterm babies with congenital disorders, incomplete medical files, refusal to enter the study, or who did not respect their routine postdischarge appointments, moved to their towns or villages.
Each neonate received 10% dextrose with electrolytes during the 1st day of life. Then, enteral feeding was initiated with colostrum in the absence of contraindication. Depending on the tolerance of the enteral feed, the daily ratio was increased at a rate of 20 ml/kg/day to a maximum of 200 ml/kg/day. Each neonate was exclusively fed with breast milk for the first 2 weeks of life, then formula adapted for preterm babies was introduced by the 3rd week. The addition of preterm formula was in the proportion of 50% breast milk - 50% formula, given that no breast milk fortifiers were available. Mixed feeding was continued till diversification was started as from 6 months.
At birth, the gestational age, birth weight, head circumference, and length of each baby were noted. During hospitalization, the weight was taken daily using the Seca™ baby scale. The length and the head circumference were measured weekly using a stadiometer and a standard measuring tape, respectively. After discharge, the children were seen monthly at the outpatient consultation unit during which weight, head circumference, and length were recorded.
We grouped the neonates according to the following chronologic ages: 0–7 days (1 week), 8–14 days (2 weeks), 15–21 days (3 weeks), 22–28 days (4 weeks), birth to 28 days (0–1 months), 29–65 days (1–2 months), 66–95 days (2–3 months), 96–126 days (3–4 months), 127–150 days (4–5 months), and 151–170 days (5–6 months).
The mean for each anthropometric parameter was calculated for each age group and for each monthly routine visit.
The data were recorded and analyzed using the SPSS version 17.0 (Chicago: SPSS inc) and the graphic representations were created using Microsoft Excel 2007. The parameters of each child in the various age groups were recorded and the mean of each parameter was calculated and represented on the graphs. The curves obtained were compared to the World Health Organization growth curves for term infants. Statistical significance was set at P < 0.05.
Ethical clearance was obtained from the YGOPH Institutional Ethical Committee for Research and informed consent was obtained from the mothers of the babies.
| Results|| |
Characteristics of the study population
Of the 113 VLBW preterm babies discharged alive from the unit during the period of study, 47 were excluded and 66 were enrolled in the study. Both sexes were almost equally represented such as 34 were females against 32 were males. Thirty-five (53%) were very preterm, born at <32 weeks of gestation and 97% of study population had birth weights between 1000 and 1499 g [Table 1].
|Table 1: Distribution of preterm VLBW neonates according to gestational ages and birth weights|
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The infants had a median birth weight of 1390 g, a median length of 40 cm, and a median head circumference of 28 cm.
Growth in weight, length, and head circumference during the first 6 months of life
There was on average stagnation of the weight during the 1st week of life. Weight gain started from the 2nd week. The mean daily weight gain during the hospitalization period calculated from the 2nd week of life was 19.5 g/kg/day in the males and 15.2 g/kg/day in females, but the difference was not statistically significant (P = 0.691 > 0.05). The overall average daily weight gain was 17.35 ± 1.53 g/kg/day. This was followed by a sharp, steady increase from the 2nd month of life in both sexes [Figure 1].
There was a steady increase in length from birth, with an average increase of 3 cm/month for females and 3.43 cm/month for males. The difference was not significant (P = 0.451 > 0.05) [Figure 2].
The head circumference increased gradually from birth at an average rate of 2.5 cm/month for males and 2 cm/month for females. The difference was not significant (P = 0.468 > 0.05) [Figure 3].
Catch-up growth of very low birth weight infants with term neonates using World Health Organization curves
The weight gain was faster from 2 months of age as could be seen from the steepness of the curves. By the 2nd month, VLBW preterms above the 85th percentile were already in the growth corridor for term infants and by 6 months all VLBW infants grew like term babies. This growth pattern was similar for both sexes [Figure 4] and [Figure 5].
|Figure 4: Comparison of weight gain in VLBW preterm with term babies on WHO curves (males)|
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|Figure 5: Comparison of weight gain in very low birth weight preterm with term babies on WHO curves (females)|
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Only VLBW infants with length at birth above the 85th percentile entered the growth corridor for term babies by the chronologic age of 6 months [Figure 6] and [Figure 7].
|Figure 6: Growth in length of very low birth weight preterm compared to term babies (males)|
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|Figure 7: Growth in length of very low birth weight preterm compared to term babies (female)|
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The head circumference in both sexes increased gradually from birth. Those with head circumference at birth at or above the 50th percentile at birth were comparable to term babies as from the 4th month of chronologic age [Figure 8] and [Figure 9].
|Figure 8: Increase in the head circumference of very low birth weight preterm compared to term babies (male)|
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|Figure 9: Increase in the head circumference of very low birth weight preterm compared to term babies (female)|
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| Discussion|| |
Using data collected in the course of clinical care, we describe the pattern of postnatal and short-term growth in a cohort of VLBW preterm infants at the YGOPH.
Limitations of the study
The respect of postnatal visits was poor with only 58% of all the babies with VLBW regular. The large number of dropouts could be a source of bias in our results. The weight, length, and head circumference measurements were not done by the same person during outpatient visits which could be a source of error.
From our results, only 58% of the VLBW infants discharged from the neonatal unit respected their appointments were followed up regularly and included in the study. This is lower than the 83% follow-up rate obtained by Ehrenkranz et al. in the USA. This could be due to the organization of our health system, financial constraints, misinformation or lack of information, and that most parents only attend clinic when they feel their children are unwell. The children admitted in this hospital come from all over the region; some of the children went back to their towns and villages and so were lost to follow-up.
The babies in this cohort were placed on mixed feeding to improve on the protein and energy intake, and feeding of the baby was evaluated during each visit. Studies done on the nutritional needs of very preterm and VLBW babies reveal the need for very high protein, energy intake for appropriate growth to occur,,,,, and there is evidence that breast milk alone might not be sufficient for the VLBW infants ,, and therefore the need for fortification. Complete parenteral nutrition is not possible in our setting and breast milk fortifiers are not available in our markets; hence, the preterm formula was used to fortify the breast milk for these infants.
We noted that 53% of the babies were very preterm born between 27 weeks and ≤32 weeks of gestation and the birth weights for 97% of the study population varied between 1000 g and 1499 g. Survival of smaller and younger babies is still poor in our institution considering the lack of respiratory (surfactant) and nutritional (parenteral nutrition) support.
Following an initial weight loss in these infants, steady weight gain was achieved after the 2nd week of age. Weight stagnation during the 1st week of life had been reported by Anchieta et al. in Portugal, Cole et al. in the United Kingdom, and other authors.,,,,,, The ultimate goal of neonatal intensive care of preterm babies is to mimic intrauterine growth, but this is difficult to achieve because of increased energy consumption (due to respiratory distress, hypothermia, infection, etc.,), seen in the preterm infant ex utero., Furthermore, digestive tract immaturity in very preterm babies renders the desired nutrient supply difficult.
Catch-up of birth weight occurred from the 2nd week of life, similar to the findings of Were and Bwibo in Kenya  and other authors in developed countries.,,,,,,,,,,,, The mean daily weight gain during the neonatal period calculated from the 2nd week of life was 19.5 g/kg/day in the males and 15.2 g/kg/day in females, and the overall average weight gain in the population was 17.35 g/kg/day similar to the findings of Cole et al. in the United Kingdom  and Ehrenkranz et al. but higher than the 12 g/kg/day in the population of Were and Bwibo. The ideal pattern of postnatal growth for preterm babies is unknown; however, the expected weight gain range is 15–30 g/kg/day for VLBW preterms.
There was rapid weight gain beyond the age of 2 months in both sexes. This implies that with adequate nutrition even after a period of growth retardation, catch-up growth occurs at some stage. In this cohort, catch-up with term babies occurred as from the chronologic age of 2 months and by 6 months all our infants were in the growth corridor for term babies. Our results are similar to the findings of Anchieta et al. in Portugal  but differ from those of Casey et al. who observed catch-up only from the 12th month of postnatal age. The difference could be explained by differences in the study population and the degree of postnatal growth restriction before catch-up growth.
Despite the weight gain in our cohort, the increase in length and head circumference was not substantial. Male infants presented a higher increase in length than the females, 3.43 cm/months (0.86 cm/week) against 3 cm/months (0.75 cm/week), but the difference between the means was not statistically significant. The difference seen in the growth of both sexes could be attributed to the effects of sex hormones like androgens. These results are comparable to the findings of Ehrenkranz et al. who recorded a weekly increase in length of 0.9 cm/week but lower than the rates of intrauterine length increase of 1.1 cm/week reported by Lubchenco et al. between 26 and 36 weeks of gestation. In our cohort, only babies with lengths above the 50th centile entered the growth corridor for term babies by 6 months of chronologic age. These findings are similar to those of Casey et al. who did not register any catch-up in length until 12 months of corrected age  but different from those of Anchieta et al. who found a satisfactory increase in length by the age of 12 weeks. The difference could be due to the difference in gestational age, birth weight, and degree of postnatal growth retardation before catch-up growth, as well as feeding method in the early neonatal period. During the 1st days of life, our patients virtually received only glucose but the patients in the cohorts of Casey et al. and Anchieta et al. received total parenteral nutrition limiting the degree of postnatal starvation and growth retardation seen in our cohort. Some authors have shown a correlation between early nutrient supply, weight gain, and neurodevelopmental outcome in infancy.,,, Nutrient deficiency during the 1st week has been shown by various research groups to account for postnatal growth retardation that can even persist into childhood and beyond., 11, ,,,,, The babies in our cohort suffered a significant starvation during the early neonatal period. The resultant postnatal growth retardation could result in a poor developmental outcome.
The increase in the head circumference in the males was faster than that of the females, 2.5 cm/months (0.63 cm/week) against 2 cm/months (0.5 cm/week), but the difference was not statistically significant. These values are lower than the 0.9 cm/week recorded by Ehrenkranz et al. Anchieta et al. noted a progressive increase in the head circumference until the age of 12 weeks. The babies in our cohort, born with a head circumference above the 50th centile, had head circumference comparable to those of term babies by 6 months of chronologic age. These results differed from those of other workers ,,,,, who observed catch-up in head circumference in their cohorts as early as 12 weeks postnatal age. Hack et al. found that by 8 months of age only 13% of VLBW babies in their cohort had a subnormal head circumference. The difference could be as a result of nutrient provision during the 1st week of life, critical for brain development. Much has been done on early nutrition, growth velocity, and the neurodevelopmental outcome of VLBW infants. It has been found that provision of high protein and energy diet during the 1st week of life are crucial for the adequate development of the brain and determinant for the neurodevelopment of these infants.,,,,,,,,,,,,,,,, The head circumference correlates with brain volume and neurodevelopmental outcome. Ehrenkranz et al. noted statistically significant, positive correlations between body weight, length, head circumference, and mid upper arm circumference increments. Sices et al. in the United States in 2006 noted a delay in progression of weight, length, and to a lesser extent head circumference in preterms with birth weight <1000 g after the neonatal period. Extremely low birth weight (ELBW) preterms represented only 3% of our sample because ELBW generally dies; this could explain the difference observed in both studies. We did not study the correlation between the anthropometric measures but noted that catch-up in length and head circumference lagged behind the weight.
| Conclusions|| |
VLBW infants showed postnatal retardation in the 1st month of life, but catch-up in weight with term infants occurred by 6 months postnatal age. However, growth in length and head circumference lagged behind. These infants need to be followed up closely for their neurodevelopmental outcome.
This study was conducted with the valuable help of the staff of the nursing and archives services of the YGOPH.
We thank Mr. Ewane Sergio for his help in data analysis and generation of the curves.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9]