Preterm and late preterm infants : their differences and breastfeeding

Objetivo: verificar se há diferenças entre recém nascidos prematuros e prematuros tardios no que se refere ao tempo de aleitamento materno e aleitamento materno exclusivo causas e consequências do desmame precoce. Ademais, foi observado o uso de oxigenoterapia e sonda para alimentação, número de sessões de fonoterapia e o tempo de internação. Métodos: pesquisa de campo, de caráter exploratório e longitudinal. Participaram do estudo 82 mães de prematuros. Os dados categóricos foram resumidos através de frequência absoluta e relativa ao total de pacientes em cada grupo estudado. Dados numéricos foram resumidos em média, mediana, desvio padrão, valor mínimo e valor máximo. Os dados quantitativos foram comparados com o teste não paramétrico de MannWhitney e as variáveis qualitativas foram comparadas com o teste de igualdade de duas proporções. Resultados: houve significância estatística entre recém-nascidos prematuros e recém-nascidos prematuros tardios para as variáveis Apgar, tempo de internação, tempo de uso da sonda, número de sessões de fonoterapia, tempo de oxigenoterapia e tipo de ventilação mecânica. Conclusão: a presente pesquisa mostrou que os prematuros tardios apresentaram menor tempo de uso de sonda e oxigenoterapia, menor número de sessões de fonoterapia e menor tempo de internação hospitalar, fazendo-se imprescindível um olhar diferenciado entre os dois grupos de prematuros.

consists of 64 preterm infants up to 33.6 weeks gestational age and Late Preterm Newborns (LPN) with 18 preterm infants between 34 and 36.6 weeks.
The inclusion criteria of individuals in the study were mothers of preterm babies up to one year old.And the exclusion criteria were mothers of preterm babies diagnosed with genetic syndromes, oral motor and/or congenital malformations or previously diagnosed neurological problems.
The mothers, legal guardians of the babies, were informed of the purpose of the research, read and signed the Informed Consent Term and answered a standardized questionnaire developed by the authors, being the same divided into baby's and mother's identification data, hospital information, experience with breastfeeding, early weaning causes, which was divided into four groups (educational, cultural, socioeconomic and anatomofunctional factors) and consequences of early weaning (diarrhea, pneumonia, harmful oral habits and infections).
Additional data collection was carried out from the records of premature infants, for variables, such as: type and duration of oxygen therapy, it was made use of superficial O 2 , tube type and usage time, number of speech therapy sessions, type of oral diet In the transition phase, place and length of hospital stay.To this end, the Risk Protection and Confidentiality Term was carried out.
The sample was collected in the period from August 2008 to November 2009.During the study, 47 mothers of preterm infants were followed up and for the remaining it was just accomplished the interview because they had already done early weaning.The primary variable of this study was gestational age.
In descriptive statistics, categorical data were summarized by means of absolute frequency (N) and on the total number of patients in each group (%).Numerical data were summarized by means of statistics such as: mean, median, standard deviation, minimum and maximum values.Quantitative data was compared with the nonparametric Mann-Whitney test and qualitative variables were compared to the test of equality of two proportions.
Statistical significance was set at p <0.05.The analysis and graphics were performed with the use of the software: SPSS V16, Minitab 15 and Excel Office 200si

RESULTS
In the present study the average gestational age was 35 weeks, 78% of the sample was PN and 22% were late PN.Regarding exclusive breastfeeding time in preterm, the average value was of 121.6 days Program to Breastfeeding mother, the inauguration of the Human Milk Banks, the Declaration of the Innocenti, the creation of the Initiative Baby Friendly Hospital strategy, the creation of the Initiative Unit Baby-Friendly and support groups in encouraging breastfeeding, in addition to national campaigns encouraging breastfeeding.
Nevertheless, there are still significant differences between premature infants less than 34 weeks gestational age and late preterm infants.The first ones may not be able to breastfeed because they are neurologically immature¹, require greater technological support and longer hospital stay and are more prone to complications during the hospital stay.
Thus, the objective of this study is to verify the differences between preterm and late preterm infants with regard to the duration of breastfeeding and exclusive breastfeeding, causes and consequences of early weaning.Furthermore, the use of oxygen therapy and feeding tube, the number of speech therapy sessions and the length of hospital stay were observed.

METHODS
The project was approved by the Research Ethics Committee of the Health Sciences State University of Alagoas/ Universidade Estadual de Ciências da Saúde de Alagoas (UNCISAL) and the Federal University of São Paulo/ Universidade Federal de São Paulo (UNIFESP), under protocol no745/07 and 1226/09, respectively.It is a prospective longitudinal field study.
For this research we carried out the sample size calculation for a proportion of finite population, held in an electronic calculator, available on the website http://lia.uncisal.edu.br/ensino/pdf2/CTA_Media_finita.xls,whose value of population (N) considered was of 2.659 children, a value obtained from the DataSUS website for the number of premature children born in Singapore in 2008.The estimated value of the reduced variable (Z) was 1.96 for an alpha value equal to 0.05 and the ratio (p) in this study was 0.5 and the tolerable error consideration (E) is equal to 0.1.The considered confidence interval was set at 95%.
The participants were 93 mothers of preterm babies who were born in the Santa Monica Maternity School, however, 82 questionnaires were analyzed, as three mothers did not attended the second appointment and eight other mothers had twin children, and the need to disregard one of the children by draw to not generate a statistical error of data duplication.To compare premature, it was established two groups: Preterm Newborns (PN)

Consequences of early weaning
Parafunctional Habits Children who were on mechanical ventilation for a long period present a delay in the development of the swallowing function 18 .As in the aforementioned studies, in the present study the preterm infants with gestational age less than 33.6 weeks made use of oxygen for a longer period, since the lower the gestational age, less development and maturation of the baby and more susceptible to neonatal morbidities compared to preterm infants with gestational age.When comparing the PN groups with late PN, we observed that the variables of birth weight, age and maternal education, probe usage time, duration of breastfeeding and exclusive breastfeeding were not statistically significant.
Despite the difficulties encountered by preterm infants of lower gestational age, in the present study 73.4% of preterm infants up to 33.6 weeks and 94.4% of late preterm infants were breastfed up to six months or more.In another study the breastfeeding occurred until the first 30 days of life in 98.1% of cases and in the sixth month there was a drop to 70.1% 19 .Research had with finding the median breastfeeding of 199.8 days, where in the first month 90.4% of the children were breastfed, in the fourth month 64.7% and in the sixth month 54.4% 20 .This is due to a multidisciplinary team specializing in Kangaroo Mother Method that held the appropriate assistance to the mother-baby and their family.
In terms of exclusive breastfeeding, the premature group to 33.6 weeks the mean value was 123.2 days and late preterm 124.3 days.Still, 42.2% of premature infants with gestational age were exclusively breastfed against 55.5% of late preterm.The time of exclusive breastfeeding of infants up to one month old was of 64.8% and of six months old this figure fell to 9.6%.For breastfeeding, the prevalence in the first month was of 98.1% and for the sixth month of 70.1% 19.Exclusive breastfeeding rates were found in the first month of 62.1% and in the sixth month of 17.7% 21 .The rates of breastfeeding in preterm infants are still below the recommended by the WHO in all reported studies.
Comparing the groups for qualitative variables (Table 2), it was found that there was a greater number of children who are small for gestational age (SGA) in the group of late PN (80 %), with statistical significance between the groups.The SGA infants have a higher risk of neonatal death than those who did not show signs of intrauterine growth delay 22 .Late premature with fetal growth restriction showed a greater time of stay in the ICU and neonatal complications than appropriate for gestational age (AGA) 17 .It is believed that this difference should be occurring because of dichotomized variables that present 67% efficiency, with a

DISCUSSION
In the present study 86.6% of the newborns presented Apgar scores between 8-10 in the 5 th minute of life, 12.2% between 7-4 and 1.2% with Apgar of three or less.Study found an Apgar score between 9/10 in 72% of cases in the 5th minute of life 13 .In another study, the Apgar score of eight or more was found in 87% of NBs 8 .The data was similar in both studies perhaps because it was the same population, preterm infants.
In the present study the average hospitalization of preterm infants was 38.2 days, ranging from 13 to 122 days.By distributing preterm in groups, those who had gestational age up to 33.6 weeks showed an average hospital stay of 41.4 days and the ones above 34 weeks, of 24.3 days.Research has found that 67% of NBs remained hospitalized for 30 days or less 14 .The results of both surveys are similar, but in the first, time of hospitalization was slightly higher since it is referral maternity care to pregnant women at risk.
In the current study, the length of stay of preterms and late preterm infants in the ICU was of 13.5 and 1.1, respectively.Study subdivided premature into groups according to weight and gestational age, and it was observed the time of ICU stay of 28 days for preterm infants with GA of less than 30 weeks, 13.3 for premature between 30 and 33.6 weeks and 9.8 days for preterm of 34 weeks or more.But the length of hospital stay was equal to 36.6, 25 and 24.3 days, respectively 15 .No studies were found that recount the time of hospitalization for preterm infants in neonatal intensive care unit and intermediate care.The difference found in both studies may be due to the fact that in the first study, it was not taken into account the birth weight.
The average number of speech therapy sessions for preterm was equal to 5.1.Premature up to 33.6 weeks showed an average of speech therapy sessions greater than the late preterm, 5.7 and 3.7, respectively, with statistical significance between the groups.In a case study with two preterm twins, were performed 10 sessions of speech therapy 16 .The difference between the studies is due to the characteristics of the sample or even because it is a sample of 82 babies in comparison with a case study with 2 twins.
Regarding the time of use of oxygen, we found out that NBs had an average of 11 days, in the group of preterm infants up to 33.6 weeks the average was 12.8 days and the group of late preterm infants was 5.8 days.A carried out research identified that 90% of PN received oxygen therapy for 2.8 days and the time on mechanical ventilation was significantly shorter, the older gestational age and birth weight 17 .
was also the main consequence of early weaning.Authors observed a significant correlation between weaning and the use of pacifier and bottle 19,24,25 .Breastfed children up to one month of age who used a pacifier, had a 2.8 times greater chance of being weaned by the sixth month 19 .Pacifier sucking habits, bottle feeding may have contributed to premature weaning and possible changes in the evolution of oral sensorimotor system 6 .
Also in this study, the deleterious oral habits were presented as the main effect of early weaning.Perhaps the harmful oral habits that mix as cause and consequence of early weaning since in our country the culture of pacifier and bottle usage is very deeply rooted in our families, as well as the premature weaning leads to not preparing the speech organs and as a result, the need for baby's sucking is not satisfied, thus the use of an artificial suction nozzle becomes necessary, even if bringing future damage because they are not the most appropriate way of stimulation for them.

CONCLUSION
The present research has shown that there are significant differences between preterm and late preterm, where the last show fewer complications, fewer speech therapy sessions, shorter hospital stay, moreover, the preterm of up to 33.6 weeks require a longer hospital support as use probe and ventilatory support, and although not statistically significant, they had shorter breastfeeding and exclusive breastfeeding, as well as increased presence of parafunctional habits, when compared to preterm late, becoming indispensable a different look between the two groups of preterm infants.great loss of susceptibility of the study, which may lead to spurious findings in the statistical analysis.
With regard to the variable type of ventilatory support there was statistical difference among the groups for all types surveyed.Late preterm have not made use of endotracheal tube, while 34.3% of preterm infants under the age of 33.6 weeks needed to be intubated.No studies were found that differed the types of respiratory support in preterm infants, becoming necessary additional studies to clarify the effect of each of these perinatal brackets in the development of the respiratory system of the preterm.
The other variables: gender, birth type, occupation and maternal marital status, dietary transition, causes and consequences of weaning showed not statistically relevant in the current research.
In the present study 58.2% of preterm and 46.7% of late preterm infants were weaned early (Table 3).
In the present study the causes of early weaning (Table 1) were caused by educational and cultural factors for both groups, the socioeconomic and anatomical and physiological factors were not reported by the mothers of preterm infants as a cause of weaning in the present study.In the same study when comparing the two groups, the preterm infants showed a higher percentage of early weaning than the late preterm for both factors.Study points out the educational causes of early weaning, being poor handling the most prominent 22 .Study shows that 17.8% of the mothers responded as cause of weaning the weak milk and 14.7% that the milk dried up 23 .

Table 1 -Comparison between Preterm infants and Preterm infants Late for quantitative variables
Key: PN: preterm newborn.;LPN: late preterm newborns; ICU: Intensive Care Unit; IC: intermediate care; R: Rooming; breastfeeding: Breastfeeding; exclusive breastfeeding: Exclusive breastfeeding.* Significant Values (p<0,05) -Mann-Whitney Test and 50% of mothers did not exclusively breastfeed their preterm infants.Results of this research are described and analyzed in tables and graphs that are presented below.

Causes of early weaning among the groups
Figure 2. Consequences of early weaning among groups