The aim of this study was to determine the proportion of preterm with poor weight gain and its predictors among preterm neonates receiving care at MNH neonatal unit. We observed that the overall proportion of preterm with poor weight gain is 86.8%. The rates of postnatal poor weight gain were high among preterm during neonatal period with no significant difference between early and late preterm. The independent predictors of poor weight gain were found to be low maternal education level, delayed initiation of the first feed, cup feeding as an initial mode of feeding and history of prior preterm delivery. All these factors could have affected the nutritional intake, in these infants who have greater nutritional needs to match their expected high rates of growth.
The overall proportion of preterm with poor weight gain observed in this study was high. Furthermore the observed average weight gain is below the goal for preterm weight gain (≥ 15 grams/kg/day) estimated to replicate the growth velocity of a normal foetus during third trimester of pregnancy(4,11–14). Poor weight gain was observed more among early preterm compared to late preterm infants, although this was not statistically significant, it may be a reflection of poor feeding as a result of feeding intolerance and also the practice in our unit during the study period of delaying initiation of feeds for at least 24 hours for this category of neonates.
Several studies have reported similar findings of high proportion in poor weight gain among preterm(3,12,15,16), contrarily other studies have found marked advancement in the growth of the preterm(17,18). The difference observed across these studies in comparison to this study could be explained by the differences in characteristics of study participants, the different existing feeding protocols and the support available for supervising feeding of these vulnerable neonates. The observed high proportion of poor weight gain among preterm neonates in this study and other studies from similar setting could be attributed to various challenges such as low level of maternal education, inadequate staffing and co morbid conditions. Furthermore, in the studied setting the units are overcrowded, mothers are responsible for feeding their infants in presence of minimal supervision and time allocated for feeding may not be adequate, since rooming in is not feasible. Additionally, the differences can be explained by different study designs used. In prospective studies like the present one especially in areas where data is appropriately captured, the missing or incomplete data may not be appreciated hence result is well reported. The differences in sample size used and duration of follow up could also contribute to these variations in growth outcomes amongst preterm.
The study population consist of preterm neonates, categorized into early and late preterm. With regarding to the findings, the proportion of poor weight gain was highest among early preterm than the late preterm neonates, and the extent of poor weight gain was shown to increase with a decrease in gestation age and these has been supported by several studies(18,19). The implication of the above findings further observed a marked percentage weight loss in first week of life in early preterm followed by a pattern of a slow gradual increase until the 4th week postnatally. This can be explained by the fact that, the initial weight loss has been attributed to various reasons such as changes in body composition seen after birth which is more pronounced in preterm babies and suboptimal absorptive capacity of immature kidneys which favours water loss(19,20). Moreover, the immaturity in body organ systems leading to the absence of coordinated swallowing and sucking reflexes especially in preterm ˂ 34 weeks GA poses difficulties with enteral feeding. These add to the pre-existing weight loss and hence contribute to postnatal growth failure among preterm. Furthermore, in presence of co-morbid conditions weight loss can be more and there may be delays in regaining birth weight.
Co-morbid conditions among preterm neonates are inevitable; due to prematurity of their body-organ systems. Preterm infants with co-morbid conditions are likely to experience poor weight than those without co-morbid conditions(21). As revealed by our study no significant association between co-morbid conditions and poor weight gain was observed. Contrary to this study, several other studies have shown that co-morbid conditions in preterm are the compelling reasons for growth deficit (3,18,19). Therefore, since co -morbidities in preterm are present due to prematurity; there is a biological plausibility to explain their influence on the weight pattern as observed in other studies above. There are possibilities that we did not capture all comorbid conditions as the diagnoses were mostly captured from the clinical notes. Thus, the few events captured did not achieve the adequate power to detect this association. Nevertheless, we cannot over emphasize the importance of early identification and treatment of comorbid complications. This has a key role in reduction of short- and long-term consequences including growth failure among preterm neonates.
Timing of initiation of enteral feeds has been shown to be a determinant of nutritional adequacy in preterm neonates. Delaying feeding (more than 48 hours) is among the factors that have been reported in this study to increase the risk of poor weight gain. The association between late initiation of enteral feeding and poor growth in preterm was similarly observed in these studies (3,18,22). Additionally, other study showed that less aggressive progression of enteral feeds might increase the incidence of poor growth failure of both early and late preterm. Findings from all these studies emphasizes the relevance of the WHO recommendation for optimal feeding, that breastfeeding should be initiated early within 24 hours of birth and infants unable to suck, breast milk to be given by other means until breastfeeding is possible(10). Delayed initiation of the first feed regardless of the reason could also cause inadequate intake of nutrients and hence affect the growth rate.
In this study cup feeding, as an initial mode of feeding was associated with higher odds of poor weight gain. There are probabilities that, these neonates received inadequate amount of feeds as a result of some spilling(23) that could have occurred during feeding and thus contributing to inadequate intake of nutrients and hence poor weight gain. Our hospital has adapted the WHO recommendations, thus the protocol at MNH neonatal unit required early initiation of breast milk in neonates and for those in alternative oral feeding method to use a cup or a nasogastic/ orogastric tube in small volumes of feeds given frequently. However as shown in this study the feeding protocols were not strictly followed which could be a result of high rates of poor growth outcome among these preterm. This represents critical area where improvement is required to ensure responsive care to facilitate early initiation of feeds and appropriate feeding method to foster a healthy growth and development among preterm and low birth weight infants.
A prior history of preterm birth was less likely to be affected by poor weight gain. Although, there are limited studies that directly explain the influence of previous history of preterm and weight gain, there are possibilities that these mothers used their experience of caring for a preterm baby before. Thus, they had more knowledge that enabled them to complying with feeding recommendations that influenced a better feeding practice and hence adequate weight gain than those who had no prior exposure.
Low maternal education independently predicted poor weight gain among the preterm. There are probabilities that those with high level of education could understand better and retain the information provided during health talks related to neonatal feeding. Thus, they were more likely to have complied with established feeding protocols, consequently, less effect on quantity and frequency of feeds. Correspondingly, these studies (3,12) reported the association of low maternal education and poor weight gain among preterm. Education always empowers mothers in all aspects and should therefore be emphasized across countries at large. Mothers, who lack or have very low level of literacy, should therefore be given extra support and supervision during feeding to assist them in caring for their preterm babies. Special attention is required to ensure adequate feeding, proper caretakers counselling and early evaluation in all preterm neonates to optimize their growth. Future studies are needed to determine other predictors of poor weight gain among preterm neonates that were beyond the scope of this study.
Our study findings should be interpreted bearing the following limitations in mind. The estimated GA may not always be accurate since some of them were based on last normal menstrual period of the mothers/ Ballard score. Foetal ultrasonography is the most accurate technique for estimating gestational age in antenatal clinic, however it is not routinely done and most mothers cannot afford. We were not able to use a dry weight since it was not feasible to starve these neonates. Challenges when measuring weight for neonates who were very sick and kept on CPAP. However, the weights were measured using a calibrated scale and was found to be consistent after being weaned off CPAP. The recorded information was obtained from the mothers and some from the clinical files such as co-morbid conditions hence recall bias and incomplete documentation respectively. This could have resulted in underestimation of these co-morbidities and hence lack of adequate power to detect the true difference between co-morbid condition and poor weight gain.
Furthermore, the knowledge score used in this study was self- created based on modified questions from WHO’s guidelines on optimal feeding of a preterm(10). However, these were normal questions derived from basic information recommended by WHO to be used for health education given to the mothers during breastfeeding sessions.