Purpose: To analyze the factors which are associated with growth delay and malnutrition in preterm infants during first year of life.

Conclusion: Evaluation data of monofactor analyze in group of low body weight (LBW) infants showed statistically significant correlation of growth delay (GD) with late gestosis of pregnancy (OR-3,56), IUGR in a newborn (OR-4,40), formula feeding (OR-9,69) and anemia of a newborn (OR5,73). To optimize health care in preterm infants it is necessary to consider the factors which correlate with GD and give the recommendations how to prevent or treat pathological and deficit conditions.

Keywords: preterm infant, growth delay, risk factors, GD

GD, growth delay; LBW, low body weight, VLBW, very low body weight; NEC, necrotizing enterocolitis; ART, assisted reproductive technologies

Prematurity is the leading cause of newborn deaths and now second-leading cause of under 5 mortality after pneumonia. 15 millions babies are born preterm every year. Over 1 million children die each year due to complications of preterm birth. The rates of preterm birth are 5-18% in different countries and rises every year. In Europe it occurs in 5-9%.^1–7

Nowadays there are many reports which show and analyze the latest methods of perinatal medicine, and the majority gives information about outcomes of prematurity at the time of birth or admission from the hospital. In only 15,8% of researches held in low and middle outcome countries, authors followed-up infants for 2 years or more and less than 50% included studies report on growth outcomes.^5,8–12

It is known that preterm birth is associated with postnatal growth and psychomotor delay and an increased risk of morbidity. The question of the hour is to study factors which affect the postnatal growth delay and malnutrition in preterm infants.

The intrauterine fetal growth and risk of preterm labor depends on various exogenous and endogenous maternal factors. Kerstjens JM et al.,¹³ showed that intrauterine growth restriction (IUGR), maternal pregnancy obesity, being one of multiple, male sex were associated with the risk of developmental delay in early childhood in moderately preterm infants¹³ Also maternal distress is associated with low body weight and prematurity.^14,15

Van der Reijden-Lakeman et al.,¹⁶ reported that children with IUGR have high risk to be short stature in future. Early growth retardation may be associated with decreased head size, and decreased later cognitive functioning.

The level of neonatal medical care plays a great role in future health of the preterm. The systematic review Gladstone M, Oliver C, Van den Broek N,⁵ revealed that the studies documenting growth outcomes for babies who had received care in well-equipped health care facility reported that there was less evidence of differences in growth between babies born preterm and term. In Kenya, where neonatal special care facilities are much more limited, only 20-28% of infants born preterm reached the lower limit of normal growth by term.^3,5

Recurrent episodes of hypoglycemia (<2.6 mmol/L or 47 mg/dL) were strongly correlated with persistent neurodevelopmental and growth deficits until 5 years of age.¹⁷ Poor postnatal weight gain in the first 2 weeks of life is an important and independent risk factor for retinopathy of prematurity requiring treatment.¹⁸

Extremely low body weight infants with short bowel syndrome (due to surgical treatment of necrotizing enterocolitis (NEC) were more likely to have growth failure than infants without short bowel syndrome.¹⁹ Multiple factors, including recurrent sepsis, malabsorption, postnatal steroid use, and cardiac diseases, may have contributed to poor nutritional outcome.

Having analyzed earlier the cohort of HIV-infected infants, we revealed that malnutrition and IUGR are more often documented in preterm babies.^20–24

Purpose

To analyze the factors which are associated with growth delay and malnutrition in preterm infants during first year of life.

The study was held 2012-2014 on the base of University Child Health clinic №1 and Odessa Regional Charitable Rehabilitation Foundation for Handiccaped Children “Futurum”. The main criteria to include a child into the range of study were gestation term under 37 weeks; body weight at the moment of birth under 2500 grams; absence of serious congenital defects and severe organic pathology. 150 children aged from 3 months up to 5 years who corresponds the criteria were selected (among them 74 boys and 76 girls) for the further analysis. All the children were divided in 3 groups depending on the birth body weight: 2^st low body weight (LBW) (2499-1500) – 67, 2^nd very low body weight (VLBW) (1499-1000) – 45, 3^rd extremely low body weight (ELBW) ( <999) – 38 patients.^25–29

General clinical examination of children with evaluation of growth and retrospective analysis of development was held. To evaluate growth we made anthropometrical measurements following the order of Ministry of health of Ukraine №149 from 20.03.2008 “On acceptance of clinical Protocol of medical care of a healthy child under 3 years of age”. The information we got was rated correspondingly: centile tables for preterm infants aging from 22 up to 50 weeks of gestation (Fetal-infant Growth Chart for preterm infants, WHO, 2006); graphics of standard deviations of physical development for children from 0 up to 5 years (WHO, Z-scores). We used anthropometrical calculator WHO Anthro, SISA online calculator to analyze achieved data. During the statistical analysis we studied the indicators of the growth of the children of the age 6 and 12 months.

No significant differences were noticed in sex of patients. In the 2^st group 33 boys and 34 girls were examined, in the 2^nd – 23 boys and 22 girls, in the 3^rd – 18 boys and 20 girls. The average term of gestation was 34,42(±2,11) weeks in the 2^st group, 29,76(±1,93) weeks in the 2^nd group and 27,32(±1,86) in the 3^rd group. Average birth body weight and birth body length were 1928,9(±264,64)g & 43,42(±2,76)cm, 1277,36(±139,16)g & 38,77(±2,24)cm, 908,47(±81,66)g & 35,86(±3,23)cm respectively. The coefficient of variation of all the calculations did not exceed 13,8%.

Frequency of growth delay (GD) among the children aged 6 months was 26,87%, 95%CI [17,72;38,52] in the 2^st group; 77,78%, 95%CI [63,73;87,46] in the 2^nd group; 100% in the 3^rd group. Frequency of GD among the children aged 1 year was 7,46%, 95%CI [3,23;16,31], 33,33%, 95%CI [21,36;47,93], 63,16%, 95%CI [41,04;80,85] relatively.

Malnutrition (deficit of weight concerning the body length) was noticed among the children aged 6 months with the following frequency: 5,97%, 95%CI [2,35;14,37] in the 2^st group, 33,33%, 95%CI [21,36;47,93] in the 2^nd group, 47,37%, 95%CI [27,33;68,29] in the 3^rd group. Among the children aged 1 year malnutrition was documented in 2,99%, 95%CI [0,82;10,25] of children of the 2^st group, 8,89%, 95%CI [3,51;20,73] of the 2^nd group, 15,79%, 95%CI [5,52;37,57] of the 3^rd group.

At the age of 6 month the BMI in infants with VLBW and ELBW in comparison with LBW babies statistically significantly more often were lower than “-2”SD. This fact also confirms higher level of malnutrition in 2^nd and 3^rd group.

Studying the data of anamnesis vitae (life history) all children were separated in two groups: children who had GD in the age of 6 month (91 infants) and those who didn’t have (59 infants). In a heuristic way we choose features which were potentially associated with GD in preterm infants during first year of life. Maternal factors: using assisted reproductive technologies (ART), age, risk of miscarriage, gestosis, acute and chronic diseases. Infant factors: IUGR, duration of lung ventilation and tube feeding, anemia of newborn, severe asphyxia and other.

ART was used in 16,67%, 95%CI [9,80;26,91] & 8,47%, 95%CI [3,67;18,35] cases relatively. Risk of miscarriage during 2^st trimester was present in 30,56%, 95%CI [21,13;41,95] women of 2^st group and in 23,73%, 95%CI [14,69;35,97]-2^nd group; during 2^nd trimester - in 44,44%, 95%CI [33,54;55,91] & 45,76%, 95%CI [33,70;58,34] relatively. In group of infants with GD 20,83%, 95%CI [13,05;31,57] had chronic diseases, and 13,56% 95%CI [7,03;24,54] in 2^nd. Carriage of TORCH group infections were a little beat more often seen in mothers of children with GD - 33,9%, 95%CI [23,14;46,63] to 22,22%, 95%CI [14,17;33,09], but it is not statistically significant.

Almost similar results were shown in both groups for age of mother ≥35 years (9,72% & 8,47%), late gestosis (15,28% & 15,25%), acute respiratory infections (16,67% & 15,25%), hydramnion and hypamnion (8,33% & 8,47%), multiple pregnancy (36,11% & 35,59%).

Analyzing the neonatal period IUGR was documented more often in GD infants - 36,11%, 95%CI [25,98;47,65], to 13,56%, 95%CI [7,03;24,54] in babies without GD. Respiratory care ≥7 days and tube feeding ≥14 days were held in 45,83%, 95%CI [34,83;57,26] & 58,33%, 95%CI [46,81;69,01] children of 2^st group and in 23,73%, 95%CI [14,69;35,97] & 35,59%, 95%CI [24,6;48,34] of 2^nd relatively. Children with GD more often were on formula feeding - 48,61%, 95%CI [37,43;59,93] to 27,12%, 95%CI [17,44;39,6] in 2^nd group. Also they more often had anemia of a newborn - 50,0%, 95%CI [38,75;61,25] to 22,03%, 95%CI [13,35;34,13]. Severe asphyxia were documented in 27,78%, 95%CI [18,76;39,05] infants with GD and only in 6,78%, 95%CI [2,67;16,18] of infants without GD.

Statistically significant difference was not shown for frequency of such complication of preterm birth like intraventricular hemorrhage (52,78% & 38,98%), severe motor delay (26,39% & 23,73%) and NEC (6,94% & 3,39%).

The monofactor analyze of chosen factors was held on the second stage of the study. The aim was to reveal the statistically significant probable difference of binary in 2^st (all infants with GD) and 2^nd (without GD) groups. The results can be observed in tab 1.1 and tab 1.2 (2^st column). Also we did the same analyze separately in babies with LBW and VLBW (2^nd & 3^rd column).

Evaluating Odds Ratio (OR) with 95%CI we didn’t found the significant association of maternal factors and presence of GD in the age of 6 month (in the total group). From infant’s factors GD was documented frequently in babies with IUGR (OR – 3,6), respiratory care ≥7 days (OR – 2,72), tube feeding ≥14 days(OR – 2,53), formula feeding (OR – 2,54), anemia of a newborn (OR – 3,54), severe asphyxia in birth (OR – 5,28).

Evaluation data of monofactor analyze in group of LBW infants showed statistically significant correlation of GD with late gestosis of pregnancy (OR – 3,56), IUGR in a newborn (OR – 4,40), formula feeding (OR – 9,69) and anemia of a newborn (OR – 5,73). There were not found statistically significant difference of OR in VLBW infants for all factors. This may be due to general immaturity of those babies and requires further multifactorial analysis. To optimize health care in preterm infants it is necessary to consider the factors which correlate with GD and give the recommendations how to prevent or treat pathological and deficit conditions.

None.

The authors declare no conflict of interest.

None.

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