Feeding patterns of full-term and preterm infants at forty weeks postconceptional age

Little research exists that addresses the differences in feeding skills between preterm (PT) infants at term and full-term (FT) infants. The purpose of this study was to quantify and examine the differences in sucking abilities of PT infants when measured at 40 weeks postconceptional age (PCA) and newly born FT infants. The sample consisted of 213 infants who were divided into three groups on the basis of their gestational age at birth (24-29 wk, 30-32 wk, and 38-42 wk). The Kron Nutritive Sucking Apparatus (KNSA) was used to examine the microstructure of sucking and feeding behaviors. There were significant differences among the three groups in several of the sucking variables: number of bursts (p = .005), intersuck interval (p = .0212), sucks per burst (p = .0003), suck width (p < .0001), intersuck width (p < .0001), mean maximum pressure (p < .0001), and intersuck width/interburst width (p = .02). The findings from this study demonstrate the importance of both maturation at birth and experience as factors influencing feeding behaviors.     

Early oral behaviour in preterm infants during breastfeeding: an electromyographic study

The objectives were to increase the understanding of the characteristics of oral behaviour during breastfeeding in preterm infants and to validate direct observations of infant sucking. Twenty-six infants were investigated once by simultaneous observation and surface electromyography (EMG) at 32.1-37.1 postmenstrual weeks. The orbicularis oris muscle was used for data analysis, as it provided the most distinct registrations. High correlation coefficients were observed with respect to classifications of EMG data by two raters on the number of sucks per burst (r = 0.97) and duration of sucking bursts (r = 0.99). The agreement between direct observations of sucking and EMG data was high. The median for mean number of sucks per burst was 8 (range 2-33) and for longest burst 28 (5-96) sucks. Sucks with low and very high intensity constituted a median of 14 (1-94)% and 25 (0-87)% of all sucks. The range in mean sucking frequency was 1.0-1.8 sucks s(-1). Suck duration ranged from 0.6 to 1.1 s. There was a considerable variation between infants in the extent of mouthing. No association with maturational level appeared for any of the components in oral behaviour. Conclusion: EMG data provided evidence of early sucking competence in preterm infants during breastfeeding, with wide individual variations. Surface EMG and direct observation are recommended as valid methods in the evaluation of breastfeeding behaviour in preterm infants.     

The development of preterm infants' breastfeeding behavior.

Extensive scientific data are available on the development of sucking in term infants, but corresponding knowledge about preterm infants has been lacking. The aim was to describe the development of preterm infants' behavior at the breast, according to postmenstrual and postnatal age. Mothers co-operated as data collectors using the Preterm Infant Breastfeeding Behavior Scale for observations. Seventy-one singletons (born after 26.7-35.9 gestational weeks) were studied prospectively. Mothers received regular advice about breastfeeding and guidance about interaction and appropriate stimulation. Breastfeeding was initiated at a postmenstrual age (PMA) of 27.9-35.9 weeks. Mothers provided 4321 records of infants' behavior, 70% of the total breastfeeding sessions during the infants' hospital stay. Irrespective of PMA, the infants responded by rooting and sucking on the first contact with the breast. Efficient rooting, areolar grasp and latching on were observed at 28 weeks, and repeated bursts of > or = 10 sucks and maximum bursts of > or = 30 sucks at 32 weeks. Nutritive sucking appeared from 30.6 weeks. Sixty-seven infants were breastfed at discharge. Fifty-seven of them established full breastfeeding at a mean PMA of 36.0 weeks (33.4-40.0 weeks). Their early sucking behavior is interpreted as the result of learning, enhanced by contingent stimuli. We therefore suggest that guidelines for initiation of breastfeeding in preterm infants should be based on cardiorespiratory stability, irrespective of current maturity, age or weight.     

Maturational changes in the feeding behaviour of infants – a comparison between breast-feeding and bottle-feeding

Aim:  To obtain a better understanding of the changes in feeding behaviour from 1 to 6 months of age. By comparing breast- and bottle-feeding, we intended to clarify the difference in longitudinal sucking performance.
Methods:  Sucking variables were consecutively measured for 16 breast-fed and eight bottle-fed infants at 1, 3 and 6 months of age.
Results:  For breast-feeding, number of sucks per burst (17.8 ± 8.8, 23.8 ± 8.3 and 32.4 ± 15.3 times), sucking burst duration (11.2 ± 6.1, 14.7 ± 8.0 and 17.9 ± 8.8 sec) and number of sucking bursts per feed (33.9 ± 13.9, 28.0 ± 18.2 and 18.6 ± 12.8 times) at 1, 3 and 6 months of age respectively showed significant differences between 1 and 6 months of age (p < 0.05). The sucking pressure and total number of sucks per feed did not differ among different ages. Bottle-feeding resulted in longer sucking bursts and more sucks per burst compared with breast-feeding in each month (p < 0.05).
Conclusion:  The increase in the amount of ingested milk with maturation resulted from an increase in bolus volume per minute as well as the higher number of sucks continuously for both breast- and bottle-fed infants.     

Immature sucking patterns in infants of mothers with diabetes

OBJECTIVE: To evaluate immaturity of sucking patterns of infants of mothers with diabetes. STUDY DESIGN: Term infants born to mothers with gestational diabetes mellitus (16 mothers managed with insulin and 31 with diet alone) were compared with 55 matched healthy infants (control group). Sucking patterns were recorded and analyzed for number of sucks and bursts and averages maximum suck pressure, number of sucks per burst, suck width, and time between bursts. The measurements were made for feedings of 5 minutes duration with Kron's Nutritive Sucking Apparatus on the third day of life. RESULTS: Relative to the control group, newborns of the insulin-treated mothers averaged 5.2 fewer bursts and 42 fewer sucks (P = .013 and P = .04, respectively). No differences were noted for other variables tested. There were no differences in sucking patterns between newborns of diet-managed mothers and control newborns. CONCLUSION: Poorer sucking patterns were found among infants of insulin-managed mothers with diabetes. The present findings indicate some degree of neurologic immaturity during the early neonatal period.     

The effect of the odour of mother's milk on breastfeeding behaviour of premature neonates

AIM: To assess the effects of exposure to the odour of mother's milk on breastfeeding behaviour of premature neonates. METHODS: Thirteen preterm infants born at 30-33 weeks gestational age were tested. Seven infants were randomly assigned to the milk-odour condition, 6 to the water-control condition. During week 35 post-conceptual age, each baby was exposed to the appropriate odour stimulus for 120 sec. on 5 consecutive days immediately prior to a breastfeeding attempt. The breastfeeding bout following the final odour exposure session, and a second breastfeeding session shortly before the baby left the hospital, were analysed. Babies were weighed before and after each feeding session. RESULTS: During each breastfeeding session, babies in the milk-odour condition displayed longer sucking bouts and more bursts composed of >7 sucking movements, and also consumed more milk than the Control infants. The time spent in the hospital was significantly less for the milk-odour condition (median = 43 days vs. 55.5 days for Controls). CONCLUSION: Brief exposure to the odour of mother's milk prior to early breastfeeding trials had a positive effect on sucking behaviour and milk ingestion of preterm babies, which in turn resulted in a shortened stay in the hospital.     

Growth of premature infants fed own mother's milk supplied with two milk formulas

The purpose of the authors in this article was to evaluate the effects of supplementing maternal milk with two different caloric formulas on the growth of premature newborns until they reached 40 weeks of post-conceptional age. Seventy premature infants weighing < 1750g at birth were randomized: 35 adequate for gestational age (AGA) and 35 small for gestational age received maternal milk and either a special preterm formula or a modified formula. Anthropometric measurements and clinical evaluations were used to determine the nutritional status and the postnatal growth of these infants, who were analyzed in six different moments: at maximum weight loss, at return to birth weight, at definite weight gain, when exclusively fed with formula, at 2000g, and when they reached 40 weeks of post-conceptional age. The AGA premature newborns on preterm formula had greater daily weight gain, cephalic circumference increase and growth. The SGA premature newborns on preterm formula had greater daily weight gain and cephalic circumference increase observed from the third week of life onward. The AGA premature newborns on modified formula had less weight gain and smaller increments in the cephalic circumference. The SGA premature on modified formula had the worst anthropometric results. The preterm formula was more efficient than the modified formula in promoting postnatal growth of AGA and SGA premature infants. We believe that, due to their special characteristics, SGA premature should receive individualized nutritional caloric planning     

Comparison of sucking patterns at introduction of oral feeding and at term in Israeli and American preterm infants

BACKGROUND: It has been hypothesized that early initiation of oral feeding in premature infants may enhance the maturation of sucking patterns. AIM: To compare preterm infant sucking characteristics in urban level III neonatal care units in the USA and Israel. The two hospitals have different practices regarding the introduction of oral feeding. METHODS: Infants were assessed at 34-35 wk postconceptional age (PCA) and at term. Sucking parameters were assessed with the Kron's Nutritive Sucking Apparatus. RESULTS: 70 infants (38 Americans and 32 Israelis) participated in the study. Oral feedings were initiated earlier (32.6 +/- 4.3 vs 34.5 +/- 1.8 wk PCA, p < 0.01) and full oral feedings were reached earlier (35.4 +/- 2.8 vs 36.5 +/- 2.5 wk PCA, p < 0.05) in the USA infants. American preterm infants produced significantly more sucks (p < 0.001), had a higher suck rate (p < 0.001), more sucks per burst (p < 0.05), and a shorter interburst width (p < 0.01) at 34 wk PCA than Israeli infants. At term, American infants produced significant more sucks (p < 0.001), higher suck rate (p < 0.001), shorter intersuck width (p < 0.001), and a shorter interburst width (p < 0.05) than the Israeli infants of the same PCA. CONCLUSION: Different practices in the care of preterm infants, such as postconceptional age at introduction of oral feeding, may play a role in the development of feeding and feeding organization at term.     

Non-nutritive sucking in the healthy pre-term infant

In the infant, sucking behaviour is one of the first coordinated muscular activities. It is under the control of the brainstem. In utero sucking is observed from 13 weeks' gestation. The healthy full-term newborn infant has a very stable rhythm of alternating bursts of sucking with pauses in between. The non-nutritive sucking (NNS) patterns of 58 low-risk prematurely born infants (gestational ages between 26 and 35 weeks) were studied using a specially designed computer-based method that analyses and quantifies NNS. A total of 183 observations were analysed. The typical NNS pattern with bursts of sucking activity separated by quiescent periods was recorded in all infants studied and was already present before 30 weeks of gestation. A gradual change over time of their NNS was seen. With increased maturation the sucking activity, sucking frequency, amplitude and burst duration all increased, while the variability of the sucking frequency and the duration of the intervals between bursts declined. Post-menstrual age (PMA) was the dominant predictor of this result but gender, state of activity and weight also influenced it to some extent. Girls had more sucking activity and a higher sucking frequency than boys. State of activity affected the stability of the rhythm. The weight of the infant influenced both sucking activity and duration of separate bursts.     

Non-nutritive sucking in sick preterm infants

BACKGROUND: Non-nutritive sucking (NNS) by the newborn infant is a fundamental behaviour and is one of the first coordinated muscular activities in the fetus. Aims: Our objective is to study the NNS pattern in prematurely born infants, who had various conditions commonly associated with immaturity. METHOD: A specially designed computer-based method that analyses and quantifies components of the NNS pattern was used. SUBJECTS: The pattern of 51 clinically stable prematurely born infants (gestational ages 26-35 weeks) making a total of 206 observations were analysed and findings were compared with those obtained from 58, healthy preterm infants. RESULTS: The rhythmic NNS pattern of alternating sucking and pauses was elicited in all examined infants, the earliest at post-menstrual age (PMA) 26 weeks. The role of PMA, the dominant predictor for several sucking variables seen in the control group, became diminished for the infants with risk factors but changes were otherwise similar. The infants' sucking activity and sucking frequency increased and the variability of the pattern declined with increased PMA and weight. Follow-up of a subgroup of infants revealed fewer sucking bursts per minute, slower sucking frequency and a greater variability of the frequency and amplitudes in those infants who developed sequelae. CONCLUSIONS: It would, thus, appear that the NNS pre-programmed rhythm generator, primarily modulated by maturation in healthy preterm infants, becomes affected by known risk associated events and in infants who later develop sequelae. Quantification of the NNS pattern in preterm infants may be a valuable future component of their evaluation.     

Preterm infants’ early growth and brain white matter maturation at term age

Background

Normal intrauterine conditions are essential to normal brain growth and development; premature birth and growth restriction can interrupt brain maturation. Maturation processes can be studied using diffusion tensor imaging.

Objective

The aim of this study was to use tract-based spatial statistics to assess the effect that early postnatal growth from birth to 40 gestational weeks has on brain white matter maturation.

Materials and methods

A total of 36 preterm infants were accepted in the study. Postnatal growth was assessed by weight, length and head circumference. Birth weight z-score and gestational age were used as confounding covariates.

Results

Head circumference catch-up growth was associated with less mature diffusion parameters (P?<?0.05). No significant associations were observed between weight or length growth and diffusion parameters.

Conclusion

Growth-restricted infants seem to have delayed brain maturation that is not fully compensated at term, despite catch-up growth.     

Growth charts for monitoring postnatal growth at NICU of extreme preterm-born infants

Aim: To provide growth charts for clinical monitoring of extra‐uterine growth from birth to full‐term age, in infants born before 26 weeks of gestation, hospitalized at neonatal intensive care unit (NICU), and compare it to the commonly used Swedish preterm birth‐size reference. Methods: This retrospective longitudinal cohort comprised all infants born before 26 + 0 weeks of gestation and surviving to full‐term age (n = 162), admitted to the NICU, Karolinska Hospital during the period January 1990 to December 2002. Body weight was recorded daily, head circumference (HC) weekly and length twice a month. Results: Birth weight (BW), length and HC showed a normal distribution without significant gender difference. The majority of the infants showed a pronounced postnatal growth restriction for all growth variables with increasing deviation from the reference with age. The mean initial weight loss was 16% with nadir at 6 days of age and a mean time to regain BW of 18 days. At discharge from NICU, 75% of those initially appropriate for gestational age infants were below –2 standard deviation scores for at least one of the body size variables. Conclusion: The poor extra‐uterine growth pattern points to the need of growth curves for extra‐uterine growth of extremely premature infants.     

Development of sucking rhythm in preterm infants

We studied the ontogeny and temporal organization of non-nutritive sucking during active sleep in 6 healthy preterm infants (mean birthweight 1.1 kg (range 0.8-1.3 kg) gestational age 28.6 weeks (range 26-30 w] from 30 to 35 weeks of post-menstrual (PM) age. Recognizable rhythmical sucking bursts were recorded at 28 weeks in one infant and by 31-33 weeks in the others. Results were analyzed for the periods 30-31, 32-33 and 34-35 PM weeks. The number of bursts/min increased with age, while the duration of each burst was stable (mean 4.1 s). The pause between bursts decreased. Sucking pace within bursts increased with age which resulted in an increase in the overall rate of sucking. The coefficient of variation (CV) for intersuck time within bursts and for interburst time was computed to examine the stability of the sucking rhythm. For intersuck time the CV was relatively low and constant across ages. However, for interburst time CV was relatively large across ages. Thus, there appears to be a stability of the intraburst sucking rhythm from 30 weeks of gestation, whereas the interburst rhythm is less regular. This documentation of temporal organization in sucking from 30 weeks is one of the earliest indications of an intrinsic rhythm in human behavior.     

Resting heart rate does not predict growth in preterm infants

Background

Previous reports indicate that preterm infants with higher baseline heart rate (HR) have greater weight gain than preterm infants with lower baseline HR. To verify this correlation and the potential utility of resting HR as a bench mark for risk of extrauterine growth restriction (EUGR), we studied preterm infants born between 32 and 36 weeks gestation. Earlier gestation infants (27 to 31 weeks) were included.

Methods

In retrospective chart review we collected heart rate (HR) and growth data on 156 infants between 27.0 and 34.0 weeks gestation from birth to hospital discharge.

Results

There was a significant increase in weight gain from day 10 of life in infants with higher resting HR compared to infants with lower resting HR. However, upon controlling for birth weight and gestational age, there was no significant relationship between HR and weight gain for any gestational age group of premature infants.

Conclusions

Contrary to previous reports, there was no significant relationship between HR and growth at any gestational age after controlling for birth weight and gestational age. It is important to continue to search for a clinical marker of risk for poor growth in preterm infants and to give an opportunity for nutritional interventions which may support better growth and developmental outcomes.     

Assessment of the rectoanal inhibitory reflex in preterm infants with delayed meconium passage

BACKGROUND: There is an inverse relationship between gestational age, birth weight and the time of first neonatal bowel movement. The authors hypothesized that delayed passage of meconium might result from a delayed maturation of the recto-anal inhibitory reflex (RAIR) in premature infants. OBJECTIVE: To evaluate whether the RAIR is absent in very preterm infants 28-32 weeks postmenstrual age with delayed meconium production. STUDY DESIGN: Anorectal manometry was performed in 10 preterm infants (seven male) with delayed meconium production (no meconium in the first 48 hours). Median postmenstrual age was 30 weeks (28-31 weeks). Birth weight ranged from 780 to 1930 g (median, 1395 g). A micromanometric assembly (outer diameter, 2.0 mm) was used which incorporated a 1.5-cm-long sleeve sensor for measurement of resting anal sphincter pressure and relaxation. Four side-holes recorded anal and rectal pressures. Rectal distension was performed with direct air insufflation to elicit the RAIR. RESULTS: The time from birth to passage of meconium ranged from 48 to 105 hours (median, 82 hours). The mean anal sphincter pressure, rectal pressure, and anal sphincter oscillation frequency were 22.0 +/- 5.0 mm Hg, 6.9 +/- 2.0 mm Hg, and 9.8 +/- 1.9/min, respectively. A normal RAIR was elicited in all infants. CONCLUSION: Anorectal manometry recordings in premature infants with delayed passage of meconium showed normal anorectal pressures and a normal RAIR, suggesting that delayed meconium passage is not related to the absence of a RAIR.     

新生儿重症监护病房中早产儿营养相关状况多中心调查974例报告

目的 了解我国早产儿在出生后早期的营养状况和影响其生长的高危因素.方法 采用回顾性调查的方法 ,收集2005年1月1日至2006年6月30日10所医院早产儿的临床资料,对影响早产儿生长的危险因素进行分析.组间行X2检验,计量资料行t检验.结果入选对象1000例,收集合格调查表974份.中位胎龄32.6周,中位出生体重1732.2 g.开始喂养时间为2(1,3)d.早产配方奶喂养占77.0%,母乳+早产配方奶喂养占13.6%.肠外营养应用氨基酸占87.3%,开始使用时间为2.5(2,3)d;平均使用时间为11(6,17)d;应用脂肪乳剂占56.9%,开始使用时间为3(2,5)d;平均使用时间为12(7,18)d.住院期间总热卡达120 kcal/(kg·d)者占74.1%,达标日龄平均为(16.3±9.4)d;口服热卡达100 kcal/(kg·d)者占84.1%,达标日龄平均为(17.0±9.4)d.早产儿平均生理性体重下降幅度为出生体重的7.54%±4.7%,恢复体重日龄(10.92±5.10)d,住院期间平均体重增长速度(13.4±6.0)g/(kg·d).对696例单胎早产儿在出院时以相应胎龄的百分位数进行评价,分别有60.0%、58.9%、29.5%的早产儿其体重、身高和头围低于第10百分位,较出生时有较大幅度的提高.结论出生体重小于第10百分位、开始喂养时间晚和体重增长速度慢是导致早产儿生后生长迟缓的危险因素.积极的营养支持策略对改善我国早产儿的营养状况及远期预后有重要意义.     

Development of baroreflex control of heart rate in preterm and full term infants

AIM: To study baroreflex maturation by measuring, longitudinally, baroreflex sensitivity in preterm (gestational age 24-37 weeks) and full term infants. METHODS: Baroreflex sensitivity was quantified once a week, one to seven times, by a totally non-invasive method. RESULTS: Baroreflex sensitivity at birth was lower in the preterm infant and increased with gestational age. It also increased with postnatal age, but the values for the preterm infants at term still tended to be lower than the values for full term babies. CONCLUSION: Baroreflex control of heart rate is present in the premature infant, but is underdeveloped and increases with postnatal age. Ex utero maturation seems to be delayed compared with in utero maturation assessed by full term values. These results may reflect sympathovagal imbalance in preterm infants and could identify a population more vulnerable to stress.     

Growth-restricted premature infants are at increased risk for low thyroxine

Objective: To evaluate, in extremely premature infants, the relationship between growth restriction and early total thyroxine levels, and to determine how maternal, prenatal, perinatal and neonatal variables influence the relationship.Study design: 719 infants born at four medical centers in Massachusetts, New York and New Jersey between 1991 and 1993 were studied. Entry criteria included: gestational age 23–30 weeks, birth weight 500–1500 g, and a serum thyroxine level obtained in the first week of life. Infants born to mothers with a history of thyroid disease were excluded. Birth weight and total thyroxine level are expressed as z-scores (standard deviation units) to adjust for their relationship to gestational age.Results: In linear regression analysis, there was a 0.18 decrease in the total thyroxine z-score for each 1.0 (1 standard deviation unit) decrease in birth weight z-score (p=0.0001). Adjustment for multiple potential maternal, prenatal, perinatal and neonatal confounders failed to identify a factor or factors that could account for the observed association.Conclusions: The early total thyroxine level in extremely preterm infants was significantly associated with birth weight z-score. This relationship persisted even after adjustment for maternal, prenatal, perinatal and neonatal confounders suggesting antenatal influences. Of clinical importance, growth-restricted infants are at increased risk for early hypothyroxinemia and, possibly, to its related morbidities.