Soothing effect of amniotic fluid smell in newborn infants

[Towards an ideal environment in neonatology]

The establishment of sensory systems occurs gradually along a transnatal continuum. During premature birth, hospitalization in neonatology, through its atypical sensory stimulations, can disrupt the development of the baby's still immature brain. To promote harmonious development in children, caregivers and parents must learn to take into account their sensory expectations in order to create the most suitable environment possible for their development.

An integrative review: Human chemosensory communication in the parent-child relationship

Body odors serve as signals of kinship, with parents exhibiting a preference for the scent of their infants, and vice versa. The reciprocal perception of body odors can promote bonding through two mechanisms. Firstly, as an indirect pathway, through associative chemosensory learning, which leads to changes in proximity-seeking behaviors. Secondly, as a direct pathway, by eliciting the display of positive emotions, thereby reinforcing the mutual bond. Both mechanisms weaken as the child undergoes development due to changes in body odor expression and perception. This comprehensive review provides an overview of the current literature on chemosignals in the parent-child relationship, highlighting their significance in facilitating dyadic communication throughout the developmental span. Furthermore, future research perspectives are outlined to gain a better understanding of these benefits and, on the long run, derive potential interventions to strengthen parent child attachment.

The effects of breast milk odor on the physiological and behavioral responses caused by venipuncture pain in term infants: A clinical trial study

BACKGROUND

Pain management is very important for infants who are unable to express it verbally. Pain control is one of the nursing actions and part of their duties. This study attempted to determine the effects of breast milk odor on the physiological and behavioral responses caused by venipuncture pain in full-term infants at an educational hospital.

MATERIALS AND METHODS

This randomized clinical trial study was carried out on 3-5 days' term and healthy babies with a gestational age of 34 weeks and later in the 9-Day Hospital of Torbet Heydariyeh, Iran, 2021. The sample size, taking into account the possibility of a 10% dropout of samples included 20 babies for each group and a total of 40 babies were selected by convenience sampling. To collect data, a checklist of demographic characteristics, a registration form for physiological responses, and the modified behavioral pain scale were used.

RESULTS

The results of this study showed that breast milk odor has a positive effect on behavioral responses (P < 0.001) and also a significant relationship was observed between the effects of breast milk odor and physiological responses percentage of oxygen uptake and pulse (P < 0.001). However, no significant relationship was observed between breast milk odor and breathing variables (P > 0.05).

CONCLUSIONS

According to the results, olfactory stimulation with breast milk during venous blood sampling showed positive effects on physiological responses and pain reduction in infants. Therefore, it is recommended to use soothing stimuli such as the smell of breast milk during painful procedures in babies.

The Effect of Neonates' Exposure to Their Mother's Scent on Weight Gain: A Randomized Controlled Study

Objective: The aim of this study was to determine the effect of newborns' exposure to their mother's scent in the intensive care unit on their weight gain. Materials and Methods: This is an experimental randomized controlled study. One hundred and four neonates were included in the study. Two groups were observed in the research: the first group consisting of those exposed to their mother's scent (n = 52) and a second control group (n = 52). Data were collected with a data collection form and an infant body weight monitoring form. Significance for the study was accepted as p < 0.05. Results: Among the neonates, 61.5% were males, the gestational week of the infants was 38.49 ± 1.24, their mean weight was 3,213.32 ± 468.67 grams (g); the two groups were similar in terms of these characteristics (p > 0.05). The neonates exposed to their mother's scent at the beginning of the study were weighed, averaging 3,105.38 ± 487.69 g; at the end of Day 1 and Day 2, their mean weight was 3,150.77 ± 493.07 and 3,197.50 ± 489.06 g, respectively. It was seen that there were significant differences in the weight of the group of neonates exposed to their mother's scent before the experiment, on Day 1 and on Day 2 (p < 0.05). The neonates in the control group were weighed at the beginning of the experiment, exhibiting a mean of 3,119.42 ± 452.85 g. Their mean weight was 3,107.12 ± 463.30 g at the end of Day 1 and 3,116.63 ± 471.09 g at the end of Day 2. These differences, however, were not statistically significant (p > 0.05). Conclusion: We found that the newborns exposed to their mother's scent in the intensive care unit registered a higher increase in weight. Our recommendation is that a mother's scent be routinely factored into neonatal care in intensive care units.

Olfactory sensory and perceptual evaluation in newborn infants: A systematic review

Fetuses are able to process olfactory stimuli present in the womb and continue to show a preference for these odors for months after birth. Despite the accumulated knowledge about their early ability to perceive odors, there is a lack of validated scales for odor response in newborns. The evaluation of reactions of the olfactory system to environmental stimuli in infants has been defined by methodological theoretical approaches of experimental and clinical assessment tools. These approaches are mainly based on psychophysical approaches and predominantly use behavioral and physiological measures. Examples can be found in studies describing early abilities of newborn babies for behaviors or heart rate variability showing memory of maternal food preferences or mother's breast milk. This systematic review aimed to determine whether validated odor assessment tools can be feasibly used in studies. Particularly in light of the current COVID-19 pandemic and evidence of associated olfactory impairment resulting from SARS-COV-2 infection, the study is also motivated by the need for tools to assess olfactory function in neonates.

The Effect of the Smell of Breast Milk and Non-Nutritious Sucking on Pain Behavioral Response and to First-Time Hepatitis B Vaccine in Term Newborns

Background:

The issue of Pain Management finds special significance in infants who are unable to verbally express pain. Studies have shown that the use of non-pharmacological pain control techniques can be effective in reducing neonatal pain. The aim of this study was to compare the effects of olfactory stimulation (with breast milk) and non-nutritive sucking (with a pacifier) on the physiological and behavioral responses in term neonates to the hepatitis B vaccine.

Methods:

In this clinical trial, which was done in 2015 at the Nohom-e Dey Hospital of Torbat Heidariyeh, 90 eligible infants were randomly selected and divided into two intervention and one control groups. In the breast-milk odor group (n = 30), the neonates were exposed to the mother's odor during vaccination. In the non-nutritive sucking group (n = 30), a standard soft pacifier was used, whereas, in the control group (n = 30), no intervention was carried out. Data collection tools included demographic information forms and the Neonatal Pain Response Scale. Data were edited and analyzed using SPSS 20 software.

Results:

This study showed that there was a statistically significant difference between the mean scores of neonatal behavioral responses after intervention in the three groups (p <0.05). The mean behavioral response was 0.73 lower in the breast-milk odor group than in the control group, and the mean behavioral response in the non-nutritive sucking group was 0.6 lower than that of the control group.

Conclusion:

The results of the study showed that both olfactory stimulations with breast milk and non-nutritive sucking have a positive impact on neonatal pain reduction, nearly equally.

Olfaction scaffolds the developing human from neonate to adolescent and beyond

The impact of the olfactory sense is regularly apparent across development. The fetus is bathed in amniotic fluid (AF) that conveys the mother's chemical ecology. Transnatal olfactory continuity between the odours of AF and milk assists in the transition to nursing. At the same time, odours emanating from the mammary areas provoke appetitive responses in newborns. Odours experienced from the mother's diet during breastfeeding, and from practices such as pre-mastication, may assist in the dietary transition at weaning. In parallel, infants are attracted to and recognize their mother's odours; later, children are able to recognize other kin and peers based on their odours. Familiar odours, such as those of the mother, regulate the child's emotions, and scaffold perception and learning through non-olfactory senses. During juvenility and adolescence, individuals become more sensitive to some bodily odours, while the timing of adolescence itself has been speculated to draw from the chemical ecology of the family unit. Odours learnt early in life and within the family niche continue to influence preferences as mate choice becomes relevant. Olfaction thus appears significant in turning on, sustaining and, in cases when mother odour is altered, disturbing adaptive reciprocity between offspring and carer during the multiple transitions of development between birth and adolescence. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.

Effect of environmental exposure to a maternally-learned odorant on anxiety-like behaviors at weaning in mice

Early sensory experience, such as exposure to maternal or other environmental factors, is considered to influence neurocognitive development and behaviors. In many species, exposure to odorants during pregnancy or lactation impacts the morpho-functional development of the olfactory circuitry with changes in olfactory sensitivity, feeding behavior and food preferences at birth or later. However, few studies have investigated the impact of a perinatal exposure to odorants on the anxiety-like behavior of animals to stressfull stimuli. Here, we exposed mice to heptaldehyde (HEP) during pregnancy and lactation and measured the anxiety-like behavior of their offspring to stress-inducing novel stimuli at weaning in presence or absence of odorants. We applied a combined social and maternal separation as a stressor and measured the anxiety-like behavior in an open field (OF) in presence of two odorants, HEP or α-pinene (AP) as a control odorant. Although the presence of the odorant during the social separation did not influence anxiety-like behavior, we found that, if mice born to non-odorized mothers exhibited a decreased exploratory behavior in the presence of both odorants, the effect was restricted to AP for the mice perinatally exposed to HEP. These results show that anxiety-like behaviors during a stress-inducing event could be reduced by the presence of a familiar odorant. We propose that the recall of an early olfactory experience could contribute to the improvement of animal welfare in various situations associated with husbandry practices.

Effects of smelling amniotic fluid on preterm infant's pain and stress during peripheral cannulation: A randomized controlled trial

AIM

To investigate the effect of smelling amniotic fluid on preterm infants' pain and stress caused by peripheral cannulation.

METHODS

This was a randomized controlled trial. The study sample consisted of 80 preterm infants meeting the case selection criteria and infants were randomly assigned to each group. However, in addition to the infants excluded from the study, total number of the infants in all the groups was 61. Infants in the amniotic fluid group smelled amniotic fluid for 15 min before, during, and after the application of peripheral cannulation while those in the control group received routine care during the procedure. The Premature Infant Pain Profile was used to assess their pain levels, and salivary cortisol analysis was performed to evaluate stress levels.

RESULTS

Preterm infants in the amniotic fluid and control groups had similar baseline characteristics. However, the pain levels of infants in the amniotic fluid group were significantly lower than of those in the control group during and after the procedure. After the procedure, cortisol levels of the infants in the amniotic fluid group were lower than of those in the control group, although this difference was not significant.

CONCLUSION

The intervention of smelling amniotic fluid is a practice that can be used for reducing pain and stress of preterm infants during peripheral cannulation.

A plausible pathway of imprinted behaviors: Skin-to-skin actions of the newborn immediately after birth follow the order of fetal development and intrauterine training of movements

We hypothesize that the competence of a newborn in the first hours after birth is the direct result of behavior training that begins during the first 12 weeks of fetal life. Correlation of Widström's 9 Instinctive Stages (behaviors of the full-term newborn during the first hours after birth) with the developmental movements during fetal life demonstrate that the fetus is invested in learning specific tasks, in a specific order, that are evolutionarily necessary for survival during the first hour and beyond.

fMRI-based Neuronal Response to New Odorants in the Newborn Brain

The sense of smell is one of the oldest and the most primitive senses mammals possess, it helps to evaluate the surrounding environment. From birth, smell is an important sensory modality, highly relevant for neonatal behavioral adaptation. Even though human newborns seem to be able to perceive and react to olfactory stimuli, there is still a lack of knowledge about the ontogeny of smell and the underlying central processing involved in odor perception in newborns. Brain networks involved in chemosensory perception of odorants are well described in adults, however in newborns there is no evidence that central olfaction is functional given the largely unmyelinated neonatal central nervous system. To examine this question, we used functional magnetic resonance imaging (fMRI) in the newborn to characterize cortical response to olfactory and trigeminal odorants. Here we show that brain response to odors can be measured and localized using functional MRI in newborns. Furthermore, we found that the developing brain, only few days after birth, processes new artificial odorants in similar cortical areas than adults, including piriform cortex, orbitofrontal cortex and insula. Our work provides evidence that human olfaction at birth relies on brain functions that involve all levels of the cortical olfactory system.

Sampling, identification and sensory evaluation of odors of a newborn baby's head and amniotic fluid

For baby odor analyses, noninvasive, stress-free sample collection is important. Using a simple method, we succeeded in obtaining fresh odors from the head of five newborn babies. These odors were chemically analyzed by two-dimensional gas chromatography coupled with mass spectrometry (GC × GC-MS), and compared with each other or with the odor of amniotic fluid from the baby's mother. We identified 31 chemical components of the volatile odors from neonate heads and 21 from amniotic fluid. Although 15 of these components were common to both sources, there was an apparent difference in the GC × GC patterns between the head and amniotic fluid odors, so the neonate head odor might be individually distinct immediately after birth. Therefore, we made artificial mixtures of the major odor components of the neonate head and maternal amniotic fluid, and used psychological tests to examine whether or not these odors could be distinguished from each other. Our data show that the artificial odor of a neonate head could be distinguished from that of amniotic fluid, and that the odors of artificial head odor mixtures could be correctly discriminated for neonates within an hour after birth and at 2 or 3 days of age.

Skin-to-skin contact the first hour after birth, underlying implications and clinical practice

AIM

This paper integrates clinical expertise to earlier research about the behaviours of the healthy, alert, full-term infant placed skin-to-skin with the mother during the first hour after birth following a noninstrumental vaginal birth.

METHOD

This state-of-the-art article forms a link within the knowledge-to-action cycle, integrating clinical observations and practice with evidence-based findings to guide clinicians in their work to implement safe uninterrupted skin-to-skin contact the first hours after birth.

RESULTS

Strong scientific research exists about the importance of skin-to-skin in the first hour after birth. This unique time for both mother and infant, individually and in relation to each other, provides vital advantages to short- and long-term health, regulation and bonding. However, worldwide, clinical practice lags. A deeper understanding of the implications for clinical practice, through review of the scientific research, has been integrated with enhanced understanding of the infant's instinctive behaviour and maternal responses while in skin-to-skin contact.

CONCLUSION

The first hour after birth is a sensitive period for both the infant and the mother. Through an enhanced understanding of the newborn infant's instinctive behaviour, practical, evidence-informed suggestions strive to overcome barriers and facilitate enablers of knowledge translation. This time must be protected by evidence-based routines of staff.

Optimal Timing to Utilize Olfactory Stimulation with Maternal Breast Milk to Improve Oral Feeding Skills in the Premature Newborn

Background: Olfactory maturation is essential for successful oral feeding. Previous studies have suggested that olfactory stimulation with maternal breast milk may expedite oral feeding skills in the premature infant; however, the optimal developmental window to utilize this intervention and sex-specific responses to stimuli are largely unknown. Objectives: To determine individual responses to olfactory stimulation with mother's own milk (MOM) on feeding outcomes in premature newborns. Materials and Methods: Infants born between 28 0/7 and 33 6/7 weeks' gestation (n = 36) were randomized to receive either MOM or water (sham) stimulus during the learning process of oral feeding. Clinical and feeding outcomes were recorded. Statistical analyses examined the effect of stimulation with MOM on feeding outcomes stratified for age and sex. Results: Overall, there was no significant difference between sham infants compared with MOM infants in mean postmenstrual age of full oral feeds (sham: 35 5/7 versus MOM 36 0/7; p = 0.37). However, when stratified by gestational age (GA), infants born <31 weeks' gestation who received MOM stimulation learned to feed sooner than controls (p = 0.06), whereas infants born ≥31 weeks' gestation learned to feed later than controls (p = 0.20) with a significant interaction (p = 0.02) between the stimulus (MOM versus sham) and dichotomized GA (<31 versus ≥31 weeks). There were no sex differences in response to olfactory stimulus. Conclusions: Infants born <31 weeks' GA who received MOM stimulation learned to feed sooner than control infants and the impact of MOM is significantly different between infants born before or after 31 weeks GA. These data suggest there may be an optimal time in development to utilize maternal breast milk to expedite oral feeding maturation in the premature newborn.

Myristic acid in amniotic fluid produces appetitive responses in human newborns

BACKGROUND

A mixture of eight fatty acids (lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, elaidic acid, and linoleic acid) that are contained in human amniotic fluid, colostrum, and milk produces appetitive responses in newborns, suggesting the existence of a transition of sensorial cues that guide newborns to the maternal breast.

OBJECTIVE

To explore the ability of each of these eight fatty acids individually to produce appetitive responses in newborns.

METHODS

The study included 12 healthy human newborns<24h after birth. Using a longitudinal design, cotton swabs that were impregnated with each of the eight fatty acids and control substances (i.e., vehicle, saline, and vanilla) were placed approximately 1cm from the newborns' nostrils for 30s. Positive responses that were suggestive of acceptance included appetitive movements (i.e., suckling) and sniffing that were directed toward the cotton swab. Lateral movements of the head away from the swab were considered negative responses. Remaining stationary with no changes in facial expressions was considered indifference.

RESULTS

Compared with controls (i.e., vehicle, saline, and vanilla) and the other fatty acids tested, myristic acid produced the longest duration of positive facial responses (suckling and sniffing). No significant differences in negative facial responses were observed in response to the odoriferous stimuli. No reactions that were suggestive of disgust were observed.

CONCLUSION

A complex combination of stimuli, including the odor of myristic acid, may integrate sensory cues that guide newborns to the maternal breast.

Effects of Having Preterm Infants Smell Amniotic Fluid, Mother's Milk, and Mother's Odor During Heel Stick Procedure on Pain, Physiological Parameters, and Crying Duration

OBJECTIVE

The study aims to assess effects of having preterm infants smell amniotic fluid, mother's milk, and mother's odor during heel stick procedure on pain, physiological parameters, and crying duration.

MATERIALS AND METHODS

The study was a randomized controlled experimental research. The population of the study was made up of preterm infants receiving treatment and care at a neonatal intensive care unit, where the study was conducted between January 2015 and March 2016. The study was performed with 85 preterm infants who met the selection criteria. Infants were randomized into four groups: amniotic fluid, mother's milk, mother's odor, and control group. Data obtained were analyzed by percentage distributions, means, standard deviation, chi-square test, Kruskal-Wallis, and Dunnett's test.

RESULTS

While no significant difference was found between the groups in terms of total preterm infant pain profile score before, during, and after the heel stick procedure (p > 0.05), a significant difference was found in terms of SO₂ values (p < 0.05) and the difference was caused by the amniotic fluid group. Although no significant difference was found between the groups in terms of crying duration (p > 0.05), the amniotic fluid group had the lowest score, followed by the mother's milk group, the mother's odor group, and the control group.

CONCLUSIONS

Amniotic fluid, mother's milk, and mother's odor were not effective in preterm infants during painful procedures.

Anethol, cinnamaldehyde, and eugenol inclusion in feed affects postweaning performance and feeding behavior of piglets

The early exposure of the fetus to certain volatiles may result in a further preference for these compounds later in life and could positively affect the acceptance of feed containing a similar flavor and the zootechnical responses. The study consisted of 2 trials to determine if including Fluidarom 1003 (a commercially flavored feed additive containing >25% anethol and cinnamaldehyde and >10% eugenol; Norel S.A., Madrid, Spain, Spain) in sow and postweaning piglet diets 1) provokes the presence or absence of 3 major volatile compounds (anethol, cinnamaldehyde, and eugenol) in amniotic fluid and milk, affecting piglet performance (BW, ADG, ADFI, and feed conversion ratio) after weaning, and 2) modifies creep feed consumption and feed preference in a 2-choice test. The major compounds, anethol, cinnamaldehyde, and eugenol, were detected in amniotic fluid; however, only traces were observed in milk. The inclusion of flavor in the sow diets improved piglet consumption and growth after weaning ( = 0.001). Furthermore, the positive reward associated with the flavor included in the sow diet was stronger when piglets were offered a nonflavored creep feed ( < 0.05). Therefore, early exposure of pigs' fetuses to maternal dietary clues at the end of gestation might allow for conditioning pigs after weaning.

Early skin-to-skin contact for mothers and their healthy newborn infants

BACKGROUND

Mother-infant separation post birth is common. In standard hospital care, newborn infants are held wrapped or dressed in their mother's arms, placed in open cribs or under radiant warmers. Skin-to-skin contact (SSC) begins ideally at birth and should last continually until the end of the first breastfeeding. SSC involves placing the dried, naked baby prone on the mother's bare chest, often covered with a warm blanket. According to mammalian neuroscience, the intimate contact inherent in this place (habitat) evokes neuro-behaviors ensuring fulfillment of basic biological needs. This time frame immediately post birth may represent a 'sensitive period' for programming future physiology and behavior.

OBJECTIVES

To assess the effects of immediate or early SSC for healthy newborn infants compared to standard contact on establishment and maintenance of breastfeeding and infant physiology.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (17 December 2015), made personal contact with trialists, consulted the bibliography on kangaroo mother care (KMC) maintained by Dr Susan Ludington, and reviewed reference lists of retrieved studies.

SELECTION CRITERIA

Randomized controlled trials that compared immediate or early SSC with usual hospital care.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included 46 trials with 3850 women and their infants; 38 trials with 3472 women and infants contributed data to our analyses. Trials took place in 21 countries, and most recruited small samples (just 12 trials randomized more than 100 women). Eight trials included women who had SSC after cesarean birth. All infants recruited to trials were healthy, and the majority were full term. Six trials studied late preterm infants (greater than 35 weeks' gestation). No included trial met all criteria for good quality with respect to methodology and reporting; no trial was successfully blinded, and all analyses were imprecise due to small sample size. Many analyses had statistical heterogeneity due to considerable differences between SSC and standard care control groups. Results for womenSSC women were more likely than women with standard contact to be breastfeeding at one to four months post birth, though there was some uncertainty in this estimate due to risks of bias in included trials (average risk ratio (RR) 1.24, 95% confidence interval (CI) 1.07 to 1.43; participants = 887; studies = 14; I² = 41%; GRADE: moderate quality). SSC women also breast fed their infants longer, though data were limited (mean difference (MD) 64 days, 95% CI 37.96 to 89.50; participants = 264; studies = six; GRADE:low quality); this result was from a sensitivity analysis excluding one trial contributing all of the heterogeneity in the primary analysis. SSC women were probably more likely to exclusively breast feed from hospital discharge to one month post birth and from six weeks to six months post birth, though both analyses had substantial heterogeneity (from discharge average RR 1.30, 95% CI 1.12 to 1.49; participants = 711; studies = six; I² = 44%; GRADE: moderate quality; from six weeks average RR 1.50, 95% CI 1.18 to 1.90; participants = 640; studies = seven; I² = 62%; GRADE: moderate quality).Women in the SCC group had higher mean scores for breastfeeding effectiveness, with moderate heterogeneity (IBFAT (Infant Breastfeeding Assessment Tool) score MD 2.28, 95% CI 1.41 to 3.15; participants = 384; studies = four; I² = 41%). SSC infants were more likely to breast feed successfully during their first feed, with high heterogeneity (average RR 1.32, 95% CI 1.04 to 1.67; participants = 575; studies = five; I² = 85%). Results for infantsSSC infants had higher SCRIP (stability of the cardio-respiratory system) scores overall, suggesting better stabilization on three physiological parameters. However, there were few infants, and the clinical significance of the test was unclear because trialists reported averages of multiple time points (standardized mean difference (SMD) 1.24, 95% CI 0.76 to 1.72; participants = 81; studies = two; GRADE low quality). SSC infants had higher blood glucose levels (MD 10.49, 95% CI 8.39 to 12.59; participants = 144; studies = three; GRADE: low quality), but similar temperature to infants in standard care (MD 0.30 degree Celcius (°C) 95% CI 0.13 °C to 0.47 °C; participants = 558; studies = six; I² = 88%; GRADE: low quality). Women and infants after cesarean birthWomen practicing SSC after cesarean birth were probably more likely to breast feed one to four months post birth and to breast feed successfully (IBFAT score), but analyses were based on just two trials and few women. Evidence was insufficient to determine whether SSC could improve breastfeeding at other times after cesarean. Single trials contributed to infant respiratory rate, maternal pain and maternal state anxiety with no power to detect group differences. SubgroupsWe found no differences for any outcome when we compared times of initiation (immediate less than 10 minutes post birth versus early 10 minutes or more post birth) or lengths of contact time (60 minutes or less contact versus more than 60 minutes contact).

AUTHORS' CONCLUSIONS

Evidence supports the use of SSC to promote breastfeeding. Studies with larger sample sizes are necessary to confirm physiological benefit for infants during transition to extra-uterine life and to establish possible dose-response effects and optimal initiation time. Methodological quality of trials remains problematic, and small trials reporting different outcomes with different scales and limited data limit our confidence in the benefits of SSC for infants. Our review included only healthy infants, which limits the range of physiological parameters observed and makes their interpretation difficult.

Comparative Effect of the Smells of Amniotic Fluid, Breast Milk, and Lavender on Newborns' Pain During Heel Lance

INTRODUCTION

The aim of this randomized controlled experimental study was to evaluate the effect of the smells of amniotic fluid, breast milk, and lavender on the pain of newborns during heel lance.

METHODS

The sample of the study consisted of 102 newborn infants who complied with the sampling criteria between August and November, 2011. The newborns smelled the samples (lavender, breast milk, amniotic fluid, and distilled water) for 5 minutes before the heel lance until 5 minutes afterward. The Neonatal Infant Pain Scale (NIPS), heart rate, and oxygen saturation were evaluated 1 minute before, during, and 1 minute after the heel lance. Data were evaluated by descriptive statistics, chi-square, intraclass correlation analysis, Spearman's rho correlation, Bonferroni's advanced analysis, Shapiro-Wilk, Kruskal-Wallis, Mann-Whitney U, Friedman, and Dunnett's tests.

RESULTS

The newborns in the control group had severe pain and the newborns in the breast milk, amniotic fluid, and lavender groups had moderate pain during the heel lance (p < 0.05). While the NIPS score of the newborns in the lavender group was lower than the breast milk and amniotic fluid groups during the heel lance, it was lower in the breast milk and amniotic fluid groups than the lavender group afterward. The lowest falls in oxygen saturation and increased in heart rate were in the breast milk and lavender groups during heel the lance.

CONCLUSION

The smells of lavender and breast milk prevent the increased heart rates, NIPS, falling oxygen saturation, and reduced pain during the invasive procedures in newborns more than amniotic fluid or control group.

Physiological mechanisms, behavioral and psychological factors influencing the transfer of milk from mothers to their young

This article is part of a Special Issue "Parental Care".Producing milk to support the growth of their young is a central element of maternal care in mammals. In spite of the facts that ecological constraints influence nursing frequency, length of time until weaning and the composition of milk, there is considerable similarity in the anatomy and physiology of milk production and delivery across mammalian species. Here we provide an overview of cross species variation in nursing patterns and milk composition as well as the mechanisms underlying mammary gland development, milk production and letdown. Not all women breastfeed their infants, thus in later sections we review studies of factors that facilitate or impede the initiation and duration of breastfeeding. The results of these investigations suggest that the decisions to initiate and maintain breastfeeding are influenced by an array of personal, social and biological factors. Finally, studies comparing the development of breastfed and formula fed infants as well as those investigating associations between breastfeeding, maternal health and mother/infant interaction are reviewed. Leading health agencies including the World Health Organization and CDC advocate breastfeeding for at least the first 6months postpartum. To achieve these rates will require not only institutional support but also a focus on individual mother/infant dyads and their experience.

Effects of maternal deprivation and the duration of reunion time on rat pup ultrasonic vocalization responses to isolation: possible implications for human infant studies

In a paradigm that may serve as a translational model for maternal separation experiences of human infants in neonatal intensive care units, we examined how the duration of reunion with the dam influenced the phenomenon of maternal potentiation of ultrasonic vocalizations, in which isolated rat pups increase rates of vocalization following brief interactions with dams. We report that maternal potentiation in 12-13 day-old rats did not occur after reunions with their anesthetized dam that lasted longer than 15-min. However, after 18 hr maternal separation, isolated pups given reunions with their anesthetized dam increased vocalization rate even with reunions as long as 3 hr. Using a split-cage apparatus that prevented physical contact, the impact of 18 hr separations on maternal potentiation was partially offset by experiencing olfactory and/or auditory stimuli of the mother. These results suggest that maintaining partial maternal sensory exposure during prolonged maternal separation can reduce responses elicited by subsequent maternal separation.

Adding odor: Less distress and enhanced attention for 6-month-olds

The effect of odor on cognitive and emotional processes has been studied in adults and children, but less so in infants. In this study twenty-seven six-month-olds were presented with a video while in either an odor (pine or baby-powder) or a no odor control condition. The video was a 92-s audiovisual presentation of a woman expressing happiness and sadness, with the order of emotion counterbalanced. Infant attention (looking time) and emotional expression (smiling, crying, mouthing) were coded. Infants looked longer in the presence of odor and expressed less crying and mouthing but more smiling behavior. Presence of odor markedly reduced infant emotional distress and increased attention, suggesting that the olfactory sensory system provides cues to infants that support mood regulation and maintain attention. These results have implications for optimizing infant environments for emotional health and cognitive development.

Breastfeeding and pain relief in full-term neonates during immunization injections: a clinical randomized trial

Background

The aim of this study was to examine the effect of breastfeeding on pain relief in full-term neonates during injection of hepatitis B vaccine.

Methods

This was a randomized clinical trial. A sample of full-term neonates was randomly allocated into two groups: the experimental group and the control group. Neonates in the experimental group were breastfed two minutes before, during, and after the hepatitis B immunization and the control group were held in mothers’ arms but not fed. Pain was assessed using the Douleur Aiguë du Nouveau-né (DAN) scale measuring facial expressions, limb movements and vocal expressions. The assessments were carried out after hepatitis B immunization.

Results

One hundred thirty healthy full-term neonates were studied (65 in the experimental group and 65 in the control group). Gestational age, birth weight, Apgar score and gender did not differ between the two groups. The mean total pain score as measured by the DAN scale was 3.52 (SD = 1.37) for the experimental group and it was 6.78 (SD = 1.69) for the controls indicating a significant lower pain score for the experimental group (P<0.001). Also, there were significant differences for the three measures of DAN scale that are facial expressions, limb movements and vocal expression, between the two study groups (P<0.001).

Conclusion

The findings confirm that breastfeeding reduces pain and is effective way for pain relief during hepatitis B vaccine injection.

Trial registration

IRCT201104166206N1

Amniotic fluid or its fatty acids produce actions similar to diazepam on lateral septal neurons firing rate

Human amniotic fluid (AF) contains eight fatty acids (FATs), and both produce anxiolytic-like effects in adult rats and appetitive responses in human newborns. The medial amygdala and lateral septal nucleus function are related to social behavior, but the action of AF or its FATs in this circuit is known. We obtained 267 single-unit extracellular recordings in Wistar rats treated with vehicle (1 mL, s.c.; n = 12), human AF (1 mL, s.c.; n = 12), a FAT mixture (1 mL, s.c.; n = 13), diazepam (1 mg/kg, i.p.; n = 11), and fluoxetine (1 mg/kg, p.o.; n = 12). Compared with the vehicle group, the spontaneous septal firing rate in the AF, FAT mixture, and diazepam groups was the lowest and in the fluoxetine group the highest. Cumulative peristimulus histograms indicated that the significant change in septal firing occurred only in the AF and FAT mixture groups and exclusively in those neurons that increased their firing rate during amygdala stimulation. We conclude that human AF and its FATs produce actions comparable to anxiolytic drugs and are able to modify the responsivity of a circuit involved in social behavior, suggesting facilitation of social recognition processes by maternal-fetal fluids.

The experience of being born: a natural context for learning to suckle

Understanding the developmental origins of congenital capabilities such as sucking is fundamental knowledge that can contribute to improving the clinical management of early feeding and facilitate the onset of oral ingestion. We describe analyses in rats showing that sensory stimulation in utero and during birth establishes the newborn's sucking responses to maternal cues. We mimicked elements of labor and delivery (viz., compressions simulating labor contractions, stroking simulating postnatal maternal licking of the newborn, and postnatal thermal flux), and used them to induce postnatal respiration and nipple attachment in caesarian-delivered pups. We report herein new data showing that, by simulating a fetal rat's experience of being born, specific components of vaginal birth provide sufficient conditions for the odor learning that guides newborn's sucking responses. In contrast, the absence of in utero compressions was associated with poor sucking onset. Knowing how birth stimuli contribute to the first nipple attachment and constitute a context for learning to suckle is an important step toward better management of some early feeding problems. It can serve also as a foundation for understanding the challenges of facilitating sucking by babies born prematurely so that they do not experience the typical contingencies mediating onset of oral ingestion.

Antenatal insults modify newborn olfactory function by nitric oxide produced from neuronal nitric oxide synthase

Newborn feeding, maternal, bonding, growth and wellbeing depend upon intact odor recognition in the early postnatal period. Antenatal stress may affect postnatal odor recognition. We investigated the exact role of a neurotransmitter, nitric oxide (NO), in newborn olfactory function. We hypothesized that olfactory neuron activity depended on NO generated by neuronal NO synthase (NOS). Utilizing in vivo functional manganese enhanced MRI (MEMRI) in a rabbit model of cerebral palsy we had shown previously that in utero hypoxia-ischemia (H-I) at E22 (70% gestation) resulted in impaired postnatal response to odorants and poor feeding. With the same antenatal insult, we manipulated NO levels in the olfactory neuron in postnatal day 1 (P1) kits by administration of intranasal NO donors or a highly selective nNOS inhibitor. Olfactory function was quantitatively measured by the response to amyl acetate stimulation by MEMRI. The relevance of nNOS to normal olfactory development was confirmed by the increase of nNOS gene expression from fetal ages to P1 in olfactory epithelium and bulbs. In control kits, nNOS inhibition decreased NO production in the olfactory system and increased MEMRI slope enhancement. In H-I kits the MEMRI slope did not increase, implicating modification of endogenous NO-mediated olfactory function by the antenatal insult. NO donors as a source of exogenous NO did not significantly change function in either group. In conclusion, olfactory epithelium nNOS in newborn rabbits probably modulates olfactory signal transduction. Antenatal H-I injury remote from delivery may affect early functional development of the olfactory system by decreasing NO-dependent signal transduction.

Early skin-to-skin contact for mothers and their healthy newborn infants

BACKGROUND

Mother-infant separation postbirth is common in Western culture. Early skin-to-skin contact (SSC) begins ideally at birth and involves placing the naked baby, head covered with a dry cap and a warm blanket across the back, prone on the mother's bare chest. According to mammalian neuroscience, the intimate contact inherent in this place (habitat) evokes neurobehaviors ensuring fulfillment of basic biological needs. This time may represent a psychophysiologically 'sensitive period' for programming future physiology and behavior.

OBJECTIVES

To assess the effects of early SSC on breastfeeding, physiological adaptation, and behavior in healthy mother-newborn dyads.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 November 2011), made personal contact with trialists, and consulted the bibliography on kangaroo mother care (KMC) maintained by Dr. Susan Ludington.

SELECTION CRITERIA

Randomized controlled trials comparing early SSC with usual hospital care.

DATA COLLECTION AND ANALYSIS

We independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Thirty-four randomized controlled trials were included involving 2177 participants (mother-infant dyads). Data from more than two trials were available for only eight outcome measures. For primary outcomes, we found a statistically significant positive effect of early SSC on breastfeeding at one to four months postbirth (13 trials; 702 participants) (risk ratio (RR) 1.27, 95% confidence interval (CI) 1.06 to 1.53, and SSC increased breastfeeding duration (seven trials; 324 participants) (mean difference (MD) 42.55 days, 95% CI -1.69 to 86.79) but the results did not quite reach statistical significance (P = 0.06). Late preterm infants had better cardio-respiratory stability with early SSC (one trial; 31 participants) (MD 2.88, 95% CI 0.53 to 5.23). Blood glucose 75 to 90 minutes following the birth was significantly higher in SSC infants (two trials, 94 infants) (MD 10.56 mg/dL, 95% CI 8.40 to 12.72).The overall methodological quality of trials was mixed, and there was high heterogeneity for some outcomes.

AUTHORS' CONCLUSIONS

Limitations included methodological quality, variations in intervention implementation, and outcomes. The intervention appears to benefit breastfeeding outcomes, and cardio-respiratory stability and decrease infant crying, and has no apparent short- or long-term negative effects. Further investigation is recommended. To facilitate meta-analysis, future research should be done using outcome measures consistent with those in the studies included here. Published reports should clearly indicate if the intervention was SSC with time of initiation and duration and include means, standard deviations and exact probability values.

The effect of a familiar scent on the behavioral and physiological pain responses in neonates

There are adverse physiologic effects of pain in neonates, and effective pain management must be an essential aspect of neonatal care. In this study we assessed the effect of a nonmaternal familiar scent on the neonatal pain responses. This study included 135 neonates randomly assigned to one of three groups. During arterial puncture, one group was exposed to a vanillin scent on a gauze pad held next to their nose. They were familiarized with it the night before blood sampling by a scented gauze pad placed in the incubator next to their head for an average duration of 8.65 hours. The second group was not familiarized with the scent but was exposed to it during the procedure. The third group was neither familiarized nor exposed to the scent. The duration of crying in the familiar scent group was significantly lower than in the two other groups. Comparison of the physiologic parameters showed less variation in oxygen saturation level during arterial puncture in the familiar scent group. In this study, a familiar scent could reduce crying and oxygen consumption during arterial puncture.

Infant visual preference for fruit enhanced by congruent in-season odor

We explored the ability of infants to recognize the smell of daily foods, including strawberries and tomatoes, by using a preferential-looking-technique. Experiment 1 was conducted while strawberries were in season (from March to June) in order to enhance the frequency of participant exposure to strawberries outside of the laboratory. Thirty-seven infants aged 6-8 months were tested with a stimulus composed of a pair of photos of strawberries and tomatoes placed side by side and accompanied by a strawberry odor, a tomato odor, or no odors. Infants showed a preference for the strawberry picture when they smelled the congruent odor, but no such preference for the tomato picture. These results suggest that even young infants can recognize olfactory-visual congruency. We conducted Experiment 2 while strawberries were out of season (from July to September) to reduce participant exposure to strawberries in their daily life. Twenty-six infants aged 6-8 months were tested with a stimulus composed of a pair of photos of strawberries and tomatoes placed side by side and accompanied by a strawberry odor, or no odors. In Experiment 2, the olfactory-visual binding effect disappeared. This implies that visual-olfactory binding is triggered by an observer's experience.

Perinatal flavour learning and adaptation to being weaned: all the pig needs is smell

Perinatal flavour learning through the maternal diet is known to enhance flavour preference and acceptance of flavoured food in many species, yet still little is known about the mechanism underlying perinatal flavour learning. Previously we found positive effects of perinatal flavour learning on food intake, growth and behaviour of piglets postweaning, but no increased preference for the flavour. This suggests that flavour learning in pigs works through a reduction of weaning stress by the presence of the familiar flavour instead. The aim of this study was to investigate whether perinatal flavour learning reduces stress at weaning, and whether the effect is stronger when the familiar flavour is present in the food. Sows were offered an anethol-flavoured diet (Flavour treatment) or control diet (Control treatment) during late gestation and lactation. Flavour and Control piglets were provided with anethol either in their food (Food treatment) or in the air (Air treatment) after weaning. Preweaning and postweaning treatments did not affect food intake, preference or growth in the first two weeks postweaning but flavour treatment reduced the latency to eat (24 versus 35 hours, P = 0.02) and within-pen variation in growth (SD within-pen: 0.7 versus 1.2 kg, P<0.001). Salivary cortisol levels tended to be lower four and seven hours postweaning for Flavour piglets compared to Control piglets (4 hours: 2.5 versus 3.0 ng/ml, P = 0.05, 7 hours: 3.1 versus 3.4 ng/ml, P = 0.08). Flavour piglets played more and showed less damaging behaviours than Control piglets, indicating that the familiar flavour reduced stress around weaning. Few interaction effects were found between preweaning and postweaning treatment, and no effects of postweaning treatment. We conclude that in the newly weaned pig, perinatal flavour learning results in a reduction of stress when the familiar flavour is present, regardless of providing the flavour in the food or in the air.

Procedural pain management for neonates using nonpharmacological strategies: part 2: mother-driven interventions

This is the second of a 2-part series to provide an overview of our current level of knowledge related to nonpharmacological strategies to diminish the pain associated with commonly performed procedures in the NICU. In our first article we discussed the prevalence of repeated pain exposure in the NICU and the importance of nonpharmacological strategies specifically containment or facilitated tucking, swaddling, positioning, nonnutritive sucking, and sweet solutions. These strategies are generally nurse-driven and we believe their importance has been underutilized. In this article we will emphasize the importance of maternal presence as a mediator for pain relief. The efficacy of breastfeeding, maternal skin-to-skin care (often referred to as kangaroo care), and multisensorial stimulation such as auditory and olfactory recognition will be the primary focus of our discussion. In addition, although primarily mother-driven, these strategies are ultimately nurse-enabled, thus the importance of this connection cannot be under appreciated with respect to successful implementation in the NICU.

Opioid mediation of amniotic fluid effects on chemosensory responsiveness in the neonatal rat

The present study investigated if oral exposure to milk or amniotic fluid (AF) alters responsiveness to sensory stimulation in the neonatal rat, and whether these effects are mediated by the opioid system. Facial wiping evoked by intraoral lemon infusion was used as a measure of sensory responsiveness. Pups were tested in a supine posture, because they showed more paw-face strokes during facial wiping than pups tested prone (Experiment 1). Moreover, pups orally exposed to milk (Experiment 2) or AF (Experiment 3) showed a diminished wiping response to lemon compared to controls exposed to water. Blockade of opioid receptors with the nonselective antagonist naltrexone (Experiment 4) or the kappa antagonist nor-binaltorphimine (Experiment 5) reinstated higher levels of facial wiping after AF exposure. These findings confirm developmental continuity between fetal and neonatal behavioral responses to AF and the ability of AF to induce activity at kappa receptors of the endogenous opioid system.

Pain in neonates is different

Pain processing and management in neonates, especially preterm neonates, differs from older populations. In this review, a brief background on pain processing in neonatal life, pain exposure in Neonatal Intensive Care Units (NICU), the consequences of untreated pain, and the difficulties in treating procedural pain pharmacologically will be presented. A more detailed review of non-pharmacological interventions for procedural pain in neonates will include sensory stimulation approaches, oral sweet solutions, and maternal interventions. Some possible mechanisms for the effectiveness of non-pharmacological interventions are offered. Finally, avenues of research into similar interventions as adjuvant therapies or drug-sparing effects in older populations are suggested.

Human olfaction: a constant state of change-blindness

Paradoxically, although humans have a superb sense of smell, they don’t trust their nose. Furthermore, although human odorant detection thresholds are very low, only unusually high odorant concentrations spontaneously shift our attention to olfaction. Here we suggest that this lack of olfactory awareness reflects the nature of olfactory attention that is shaped by the spatial and temporal envelopes of olfaction. Regarding the spatial envelope, selective attention is allocated in space. Humans direct an attentional spotlight within spatial coordinates in both vision and audition. Human olfactory spatial abilities are minimal. Thus, with no olfactory space, there is no arena for olfactory selective attention. Regarding the temporal envelope, whereas vision and audition consist of nearly continuous input, olfactory input is discreet, made of sniffs widely separated in time. If similar temporal breaks are artificially introduced to vision and audition, they induce “change blindness”, a loss of attentional capture that results in a lack of awareness to change. Whereas “change blindness” is an aberration of vision and audition, the long inter-sniff-interval renders “change anosmia” the norm in human olfaction. Therefore, attentional capture in olfaction is minimal, as is human olfactory awareness. All this, however, does not diminish the role of olfaction through sub-attentive mechanisms allowing subliminal smells a profound influence on human behavior and perception.

An odor is not worth a thousand words: from multidimensional odors to unidimensional odor objects

Olfaction is often referred to as a multidimensional sense. It is multidimensional in that approximately 1000 different receptor types, each tuned to particular odor aspects, together contribute to the olfactory percept. In humans, however, this percept is nearly unidimensional. Humans can detect and discriminate countless odorants, but can identify few by name. The one thing humans can and do invariably say about an odor is whether it is pleasant or not. We argue that this hedonic determination is the key function of olfaction. Thus, the boundaries of an odor object are determined by its pleasantness, which--unlike something material and more like an emotion--remains poorly delineated with words.

Prenatal flavor exposure affects growth, health and behavior of newly weaned piglets

Young animals can learn about flavors from the maternal diet that appear in the amniotic fluid and mother's milk, which may reduce neophobia for similarly flavored food types at weaning. Flavor learning may be beneficial for piglets, which after the rather abrupt weaning in pig husbandry frequently show a period of anorexia, reduced health, and stress-induced behaviors. We investigated the effects of pre- and postnatal flavor exposure through the maternal diet on acceptance of a similarly flavored food and subsequent growth, health and behavior of newly weaned piglets. Sows were offered anise-flavored (F) or control (C) food during late gestation. Piglets were cross-fostered after birth, with each sow fostering 5 piglets from an F sow and 5 from a C sow. During lactation, sows were offered F or C food, resulting in FF, CF, FC and CC piglets. Piglets were weaned on day 25 and were given both control and flavored food for two weeks using a double food choice approach. The flavored food was not preferred. Yet, prenatally exposed animals showed a higher food intake and a higher body weight in the first days after weaning, and a lower occurrence of diarrhoea than non-exposed piglets. Prenatal exposure also increased the latency to fight, and reduced oral manipulation of pen mates and mounting during the first two weeks after weaning. Prenatal exposure, but not postnatal exposure alone, to anisic flavor through the maternal diet reduced weaning-associated problems in piglets and enhanced their health and welfare in the period after weaning.

Effects of breastfeeding on pain relief in full-term newborns

Breastfeeding may be useful for relieving procedural pain experienced by neonates. Researchers have compared breastfeeding against other pain relieving approaches in several studies, presenting marked methodologic heterogeneity.

OBJECTIVE

To investigate the effectiveness of breastfeeding in reducing pain in newborns undergoing blood collection for newborn screening.

METHOD

The sample of this randomized clinical trial study consisted of 60 full-term newborns: 31 in the experimental group and 29 in the control group. The experimental group was breastfed 5 minutes before, during, and for 5 minutes after the blood collection procedure. Neonates in the control group were held in mothers' arms but not fed or given a soother. The duration of breastfeeding was prolonged in comparison to previous studies.

RESULTS

The primary outcomes were Neonatal Facial Actions (Neonatal Facial Activity Coding System-upper face), sleep-wake state. Heart rate was considered as an index of arousal. Sucking frequency was only evaluated in the experimental group. Compared with the control group, the experimental group had significantly lower, Neonatal Facial Activity Coding System and sleep-wake state scores and heart rates changes. In the experimental group sucking frequency was highest during the first 5 minutes of breastfeeding before the procedure.

DISCUSSION

This study innovates from earlier studies in 4 respects: the different phases of the procedure were evaluated separately; the breastfeeding intervention covered the period from 5 minutes before the blood collection until the end of recovery; sleep-wake state was fully assessed (not merely crying) and the sucking frequency in the experimental group was assessed during the procedure. The conclusion was that breastfeeding was effective in reducing pain caused by blood collection for newborn screening.

Co-bedding as a Comfort measure For Twins undergoing painful procedures (CComForT Trial)

Background

Co-bedding, a developmental care strategy, is the practice of caring for diaper clad twins in one incubator (versus separating and caring for each infant in separate incubators), thus creating the opportunity for skin-to-skin contact and touch between the twins. In studies of mothers and their infants, maternal skin-to-skin contact has been shown to decrease procedural pain response according to both behavioral and physiological indicators in very preterm neonates. It is uncertain if this comfort is derived solely from maternal presence or from stabilization of regulatory processes from direct skin contact. The intent of this study is to compare the comfort effect of co-bedding (between twin infants who are co-bedding and those who are not) on infant pain response and physiologic stability during a tissue breaking procedure (heelstick).

Methods/Design

Medically stable preterm twin infants admitted to the Neonatal Intensive Care Unit will be randomly assigned to a co-bedding group or a standard care group. Pain response will be measured by physiological and videotaped facial reaction using the Premature Infant Pain Profile scale (PIPP). Recovery from the tissue breaking procedure will be determined by the length of time for heart rate and oxygen saturation to return to baseline. Sixty four sets of twins (n = 128) will be recruited into the study. Analysis and inference will be based on the intention-to-treat principle.

Discussion

If twin contact while co-bedding is determined to have a comforting effect for painful procedures, then changes in current neonatal care practices to include co-bedding may be an inexpensive, non invasive method to help maintain physiologic stability and decrease the long term psychological impact of procedural pain in this high risk population. Knowledge obtained from this study will also add to existing theoretical models with respect to the exact mechanism of comfort through touch.

Trial registration

NCT00917631

Fetal learning about ethanol and later ethanol responsiveness: evidence against "safe" amounts of prenatal exposure

Near-term fetuses of different mammalian species, including humans, exhibit functional sensory and learning capabilities. The neurobiological literature indicates that the unborn organism processes sensory stimuli present in the amniotic fluid, retains this information for considerable amounts of time, and is also capable of associating such stimuli with biologically relevant events. This research has stimulated studies aimed at the analysis of fetal and neonatal learning about ethanol, a topic that constitutes the core of the present review. Ethanol has characteristic sensory (olfactory, taste, and trigeminal) attributes and can exert pharmacologic reinforcing effects. The studies under examination support the hypothesis that low to moderate levels of maternal ethanol intoxication during late pregnancy set the opportunity for fetal learning about ethanol. These levels of prenatal ethanol exposure do not generate evident morphologic or neurobehavioral alterations in the offspring, but they exert a significant impact upon later ethanol-seeking and intake behaviors. Supported by preclinical and clinical findings, this review contributes to strengthening the case for the ability of prenatal ethanol exposure to have effects on the postnatal organism.