Changes In Maternal Behavior Research Articles

2302 Impacts of postnatal nest change on early development

OBJECTIVES/SPECIFIC AIMS: It has been reported that birth mode affects development, with cesarean section born mice gaining more body weight during development. Since mice C-sections involve fostering and nest change, we sought to determine whether changing only the nest and cage would have an effect on development. METHODS/STUDY POPULATION: A total of 53 mice were born to 9 dams, and 21 babies (4 litters) were exchanged in pairs to foreign cages and nests. Litters were followed for body weight and mothers were observed during periods for maternal and nonmaternal behaviors. RESULTS/ANTICIPATED RESULTS: The results show that average body weight was significantly higher in the experimental group in both genders, with 20% higher body weights at weaning. The mothers from the litters that were changed to a new nest showed significantly more non-maternal behavior in the first 2 days if life, than the controls. DISCUSSION/SIGNIFICANCE OF IMPACT: The results suggest that changes in maternal behavior may be linked to the increased weight gain in their babies.

Combined effect of gestational stress and postpartum stress on maternal care in rats

Variations in maternal care in the rat influence the development of individual differences in behavioral and endocrine responses to stress. This study aimed to examine the interaction between intragastric intubation during late gestation and postpartum stress, induced by pup separation, on maternal behavior and on dams' emotional state and HPA axis function. Rats received intragastric intubation of water on days 12–20 of gestation or remained untreated in their home cage (naïve dams). Pup separation was used as a model of postpartum stress. The procedure consisted of a daily separation of the dam from its litter for 3h from PND 3 until PND 15. Pup separation was carried out in both naïve and intubated dams. The behavioral results indicate that the association of these two stressors significantly decreased arched-back nursing (ABN) and licking and grooming (LG), behaviors considered important parameters to discriminate the high quality of maternal care. Moreover, dams that received both stressors displayed less nest building and blanket nursing behaviors; no effect on the frequency of passive and total nursing was recorded. The analysis of single effects on ABN and LG, revealed that dams that underwent gestational stress induced by intragastric intubation displayed less LG, but ABN was overall unchanged. On the contrary, pup separation stress significantly increased ABN and LG upon reunion of naïve dams with their pups. Treatments per se or the association of both induced modest changes in plasma levels of allopregnanolone and corticosterone that likely did not influence maternal care. These data show that the association of a mild stress during gestation with an unfavorable experience after parturition had a significant impact on maternal care. This effect seems independent from HPA axis activation or from changes in emotional state; further studies would be necessary to ascertain the neural changes that could contribute to altered maternal behavior in stressed mothers. Moreover, these results suggest that the use of intragastric intubation during gestation would interfere with measures of drug-induced changes in maternal behavior and likely their consequences on the offspring.

Low doses of 17α-ethinyl estradiol alter the maternal brain and induce stereotypies in CD-1 mice exposed during pregnancy and lactation

Maternal care is critical for the survival, development and long-term success of offspring. Despite our current understanding of the role of endogenous estrogen in both maternal behavior and the maternal brain, the potential effects of exogenous estrogens on these endpoints remain poorly understood. Here, pregnant CD-1 mice were exposed to low doses of 17α-ethinyl estradiol (EE2), commonly used as a positive control in studies of other xenoestrogens, from day 9 of pregnancy until weaning. Using traditional maternal behavior assays, we document no significant changes in maternal behavior throughout the lactational period. However, EE2 induced increases in repetitive tail retrieval, which may indicate a stereotypy or obsessive compulsive (OCD)-like behavior. We also observed a significant reduction in tyrosine hydroxylase (TH) immunoreactivity in the ventral tegmental area (VTA), a region important for maternal motivation. These results suggest that pregnant adult females are not immune to the effects of this compound.

Intervention with the mother-infant relationship reduces cell proliferation in the Locus Coeruleus of female rat pups.

The Locus Coeruleus (LC) is a noradrenergic nucleus involved in several neuroendocrine and behavioral functions. During the neonatal period, the LC is critical for olfactory learning. Full development occurs during the early postnatal period. Environmental interventions after birth may affect neurogenesis. In rats, the neonatal handling procedure has been used as a model to analyze the effects of environmental intervention early in life. It has been related to several long-lasting behavioral and neuroendocrine changes. The present study analyzed the effects of handling on the number of neurons, cellular proliferation, and apoptosis in the LC of 11-day-old female rats. Wistar rat pups were submitted to brief maternal separation followed by handling (1 min per day from postnatal day [PND] 1 to 10). On PND 11, the LC was analyzed using immunohistochemistry for NeuN and BrdU, TUNEL staining, and electron microscopy. The intervention reduced the number of neurons in the LC but showed no significant change in the number of apoptotic cells, as measured by the TUNEL technique. However, the number of proliferating cells was significantly lower in the handled rat pups as compared with the nonhandled ones. This study demonstrates that the infant LC is sensitive to changes in maternal behavior. A seemingly mild environmental intervention during the neonatal period may reprogram the development of the LC, altering cell proliferation. (PsycINFO Database Record

Oxytocin and Maternal Brain Plasticity.

Although dramatic postnatal changes in maternal behavior have long been noted, we are only now beginning to understand the neurobiological mechanisms that support this transition. The present paper synthesizes growing insights from both animal and human research to provide an overview of the plasticity of the mother's brain, with a particular emphasis on the oxytocin system. We examine plasticity observed within the oxytocin system and discuss how these changes mediate an array of other adaptations observed within the maternal brain. We outline factors that affect the oxytocin-mediated plasticity of the maternal brain and review evidence linking disruptions in oxytocin functions to challenges in maternal adaptation. We conclude by suggesting a strategy for intervention with mothers who may be at risk for maladjustment during this transition to motherhood, while highlighting areas where further research is needed.

Effect of maternal health education on physical activity and body mass index of overweight children

Background The percentage of overweight children in Bengkulu (16.4%) is higher than the national percentage (11.9%). High energy intake and low physical activity are two factors that cause overweight.Objective To assess the impact of maternal health education on changes in maternal behavior, as well as energy intake, physical activity level, and body mass index (BMI) z-scores in overweight children aged 3-6 years.Methods This study was a quasi-experiment with non-randomized, pre-post test control group, conducted in Bengkulu, Indonesia from January to April 2014. Subjects consisted of 48 mothers with overweight children, who were selected purposively and divided into 2 groups (treatment and control). Subjects’ parents kept records of their children’s food intake and daily activity. These records were used to measure energy intake and physical activity. Health education in the treatment group was conducted 6 times in 12 weeks, while the control group received health education only once at the beginning of the study.Results In the treatment group, the child physical activity level [0.04 (SD 0.01)] increased, while the % RDA for energy [-3.4 (SD 13.26)%] and BMI z-score [-0.57 (SD 0.26)] decreased. Significant differences were observed between the treatment and control groups in terms of maternal attitude, and children’s % RDA for energy, physical activity level, and BMI z-score after intervention (P <0.05).Conclusion Health education for mothers effects a positive change in maternal attitude, as well as increased physical activity level, decreased energy consumption relative to their need, and BMI z-score in overweight children.

Pengaruh Program Perubahan Perilaku Ibu Hamil (Cerdigi) Berdasarkan Teori ABC (Studi Pendahuluan di Kelurahan Serpong, Tangerang Selatan)

Kesehatan gigi dan mulut merupakan salah satu hal yang perlu diperhatikan selama kehamilan. Perilaku pemeliharaan kesehatan gigi dan mulut selama hamil masih rendah. Kondisi kesehatan gigi dan mulut ibu hamil yang buruk dapat memberikan dampak, seperti bayi lahir prematur dan berat badan lahir rendah (BBLR). Teori perubahan perilaku ABC berfokus antecedent, behavior, dan consequence. Tujuan penelitian untuk mengetahui perilaku pemeliharaan kesehatan gigi mulut ibu hamil, mengindentifikasi faktor antecedent-nya, melakukan intervensi perubahan behavior-nya (DHE), dan menganalisis consequence perilakunya. Jenis penelitian ini deskriptif dengan desain cross sectional, melibatkan 27 ibu hamil di Kelurahan Serpong, Tangerang Selatan. Pengumpulan data diperoleh melalui wawancara dan kuesioner. Hasil penelitian menunjukkan 100% (27 responden) menyikat gigi 2x/hari, 44,4% (12 responden) menggunakan obat kumur 1x/minggu dan 4% (1 responden) memeriksakan ke dokter gigi saat hamil. Faktor antecedent tidak memeriksakan ke dokter gigi saat hamil yaitu 33% tidak tahu manfaat ke dokter gigi, 26% takut ke dokter gigi, 19% merasa biaya ke dokter gigi mahal, 11% tidak merasa butuh ke dokter gigi, dan 11 takut mengganggu janin. Setelah 9 hari intervensi, 19 responden dievaluasi consequencenya dengan hasil 90% belum ke dokter gigi, 5% telah ke dokter gigi, dan 5% tidak mau ke dokter gigi. Alasan belum memeriksakan ke dokter gigi dikarenakan waktu 52%, tidak ada yang mengantar 12%, malas 12%, takut ke dokter gigi 12%, dan belum ada dana 12%. Kesimpulan penelitian adalah perilaku pemeliharaan kesehatan gigi mulut ibu hamil didominasi pemeliharaan sendiri (sikat gigi dan kumur-kumur obat kumur), sementara pemeliharaan ke dokter gigi masih rendah dengan berbagai antecedence.Maternal Behavior Change Program (Cerdigi) Based on ABC’s Theory (Pilot Study in Serpong Subdistrict, South Tangerang). Oral health is one of the things that need attention during pregnancy. However, the behavior of dental and oral health maintenance during pregnancy is still low. Poor oral health conditions in pregnant women can have an impact, such as premature births and low birth weight (LBW) babies. ABC behavior change theory focuses on the antecedent, behavior, and consequence of behavior. The purpose of this study is to determine pregnant women’s behavior of oral health maintenance, identify their antecedent factors, behavior change interventions (DHE), and analyze the behavior consequence. This was a descriptive research with a cross-sectional design among 27 pregnant women in Serpong Subdistrict, South Tangerang. The data were collected through interviews and questionnaires. The results show 100% (27 respondents) did tooth brushing twice a day, 44,4% (12 respondents) used mouthwash once a week and 4% (1 respondent) visited a dentist during pregnancy. The antecedent factors of not visiting a dentist during pregnancy were because: 33% did not know the benefits of visiting a dentist, 26% had fear of dentist, 19% felt that visiting a dentist was expensive, 11% did not feel the need to go to a dentist, and 11% had fear of disturbing the fetus. After 9 days of intervention, the consequences on the 19 respondents were evaluated and the results show that 89.5% had not visited a dentist, 5.25% had visited a dentist, and 5.25% did not want to visit a dentist. The reason of not visiting a dentist was because of having not much time 52.8%, having nobody to accompany 11.8%, feeling lazy 11.8%, still feeling afraid of a dentist 11.8 %, and having no money 11.8%. The conclusion from this study is that the most dominant behaviors of oral health maintenance in pregnant women is to maintain it by themselves (toothbrushing and using mouthwash), while maintaining the health by visiting a dentist is still low with various antecendents.

Propagation of maternal behavior across generations is associated with changes in non-maternal cognitive and behavioral processes

Over a number of years we have studied the phenomenology of maternal behavior from endocrine, neural, experiential, and ontogenetic perspectives. Here, we focus on the effects of early life experiences with and without the mother on subsequent maternal and non-maternal behaviors of the offspring. We have used an artificial rearing procedure, which entails removing rat pups from their mother and raising them in isolation, while controlling and manipulating several aspects of their upbringing. As adults, mother-reared (MR) and artificially-reared (AR) rats are assessed on their own maternal behavior, as well several other behaviors. While both AR and MR rats nurse and successfully wean their young, the AR rats spend less time licking, grooming, and crouching over their young. Hence, being raised in social isolation does not seem to affect primary maternal motivational dynamics. Instead, isolation rearing produces alterations in the ongoing execution of the behavior and its effective organization. Here, we present evidence that changes in maternal behavior, as a result of social isolation from mother and siblings, are due to changes in top-down (e.g., sustained attention, flexibility) and bottom-up process (e.g., increased stimulus-driven behavior). These changes are likely due to alterations in brain dopamine systems, which are sensitive to early life manipulations and are modulators of bottom-up and top-down processes. Finally, we draw parallels between the rat and human maternal behavior.This article is part of a Special Issue entitled: In Honor of Jerry Hogan.

Histone deacetylase inhibition induces long-lasting changes in maternal behavior and gene expression in female mice.

In many species, including mice, maternal responsiveness is experience-dependent and permanent, lasting for long periods (months to years). We have shown that after brief exposures to pups, virgin female mice continue to respond maternally toward pups for at least one month. Administration of a histone deacetylase inhibitor (HDACi) reduces the amount of maternal experience required to affect maternal behavior and gene expression. In this set of studies, we examined the epigenetic mechanisms that underlie these motivated behaviors. We assessed whether the effects of HDACi persisted 1 month after the initial experience (in the absence of continued pup experience or HDACi treatment) and whether the maintenance of maternal memory was associated with stable changes in gene expression. Using chromatin immunoprecipitation, we examined whether Esr2 and Oxt gene expression might be mediated by recruitment of the histone acetyltransferase cAMP response element binding protein (CBP) to their promoter regions after maternal memory consolidation. We report that HDACi treatment induced long-lasting changes in maternal responsiveness. Maternal learning was associated with increased recruitment of CBP to the Esr2 and Oxt gene promoters during the consolidation of maternal memory as well as a persistent increase in estrogen receptor-β (Esr2) mRNA and decreased expression of the de novo DNA methyltransferase Dnmt3a within the medial preoptic area. The consolidation of the maternal experience may involve the CBP recruitment and stable changes in gene expression, which maintain increased maternal responsiveness for long periods of time.

Effect of Maternal Care on Hearing Onset Induced by Developmental Changes in the Auditory Periphery

Handling (H) and cross-fostering (CF) rodent pups during postnatal development triggers changes in maternal behavior which in turn trigger long-term physiological changes in the offspring. However, less is known about the short-term effects of H and CF on infant development. In this study we hypothesized that manipulations of maternal care affect the onset of hearing in Wistar rats. To test this hypothesis we obtained auditory brainstem responses (ABRs) and micro-CT x-ray scans to measure changes in the development of the auditory periphery in H and CF pups manipulated at postnatal day (P)1, P5, or P9. We found evidence of changes in hearing development in H and CF pups compared with naive pups, including changes in the percentage of animals with ABRs during development, a decrease in ABR thresholds between P13 and P15, and anatomical results consistent with an accelerated formation of the middle ear cavity and opening of the ear canal. Biochemical measurements showed elevated levels of thyroid hormone in plasma from naive and CF pups. These results provide evidence that manipulations of maternal care accelerate hearing onset in Wistar rats. Understanding the mechanisms by which maternal care affects hearing onset opens new opportunities to study experience-dependent development of mammalian hearing.

The effect of maternal stress activation on the offspring during lactation in light of vasopressin.

Although it is obvious that preconceptional effects as well as stressors during pregnancy profoundly influence the progeny, the lactation period seems to be at least as important. Here we summarize how maternal stressors during the lactation period affect the offspring. As vasopressin is one of the crucial components both for stress adaptation and social behavior, special emphasis was given to this neuropeptide. We can conclude that stressing the mother does not have the same acute effect on the hypothalamo-pituitary-adrenocortical axis (as the main target of stress adaptation) of the pups as stressing the pups, but later endocrine and behavioral consequences can be similar. Vasopressin plays a role in acute and later consequences of perinatal stressor applied either to the mother or to the offspring, thereby contributing to transmitting the mothers' stress to the progeny. This mother-infant interaction does not necessarily mean a direct transmission of molecules, but rather is the result of programming the brain development through changes in maternal behavior. Thus, there is a time lag between maternal stress and stress-related changes in the offspring. The interactions are bidirectional as not only stress in the dam but also stress in the progeny has an effect on nursing.

Longitudinal associations between breastfeeding and observed mother–child interaction qualities in early childhood

Despite extensive literature on the role of breastfeeding in maternal and child health and cognitive development, few studies have systematically tested whether breastfeeding predicts children's socio-emotional outcomes. The present study examined associations between trajectories of breastfeeding and observed parent-child interaction qualities of maternal sensitivity, child positivity, and child negativity from 6 months to 3 years of age. Data were drawn from the NICHD Study of Early Child Care and Youth Development (n = 1306 US families). Hierarchical linear modelling accounted for demographic and early characteristics, including home environment, maternal depression, and observed global relationship quality. Breastfeeding was associated with increases in observed maternal sensitivity over time, even after the effects of demographic and early characteristics were controlled. Accounting for the covariates, breastfeeding was not associated with child behaviour (i.e. positivity, negativity) in mother-child interaction across early childhood. Improved relationship quality, specifically through changes in maternal behaviour, may be another advantage experienced by breastfeeding mothers and children.

Comparative Network Analysis of Preterm vs. Full-Term Infant-Mother Interactions

Several studies have reported that interactions of mothers with preterm infants show differential characteristics compared to that of mothers with full-term infants. Interaction of preterm dyads is often reported as less harmonious. However, observations and explanations concerning the underlying mechanisms are inconsistent. In this work 30 preterm and 42 full-term mother-infant dyads were observed at one year of age. Free play interactions were videotaped and coded using a micro-analytic coding system. The video records were coded at one second resolution and studied by a novel approach using network analysis tools. The advantage of our approach is that it reveals the patterns of behavioral transitions in the interactions. We found that the most frequent behavioral transitions are the same in the two groups. However, we have identified several high and lower frequency transitions which occur significantly more often in the preterm or full-term group. Our analysis also suggests that the variability of behavioral transitions is significantly higher in the preterm group. This higher variability is mostly resulted from the diversity of transitions involving non-harmonious behaviors. We have identified a maladaptive pattern in the maternal behavior in the preterm group, involving intrusiveness and disengagement. Application of the approach reported in this paper to longitudinal data could elucidate whether these maladaptive maternal behavioral changes place the infant at risk for later emotional, cognitive and behavioral disturbance.

Effects of an Early Experience Involving Training in a T-Maze Under either Denial or Receipt of Expected Reward through Maternal Contact

The mother is the most salient stimulus for the developing pups and a number of early experience models employ manipulation of the mother-infant interaction. We have developed a new model which in addition to changes in maternal behavior includes a learning component on the part of the pups. More specifically, pups were trained in a T-maze and either received (RER rats) or were denied (DER) the reward of maternal contact, during postnatal days 10–13. Pups of both experimental groups learn the T-maze, but the RER do so more efficiently utilizing a procedural-type of learning and memory with activation of the dorsal basal ganglia. On the other hand, the DER experience leads to activation of the hippocampus, prefrontal cortex, and amygdala in the pups. In adulthood, male DER animals exhibit better mnemonic abilities in the Morris water maze and higher activation of the hippocampus, while they have decreased brain serotonergic activity, exhibit a depressive-like phenotype and proactive aggressive behavior in the resident-intruder test. While male RER animals assume a reactive coping style in this test, and showed increased freezing during both contextual and cued memory recall following fear conditioning.

Paternal social enrichment effects on maternal behavior and offspring growth

Paternal environmental experiences are significant predictors of developmental outcomes in offspring and can occur even in the absence of paternal care. Although there has been a recent focus on the role of environmentally induced changes in the male germline in producing these effects, the potential mediating role of mothers has not been investigated. A role for mothers in the transmission of paternal effects has been well acknowledged in behavioral ecology, which predicts that females will dynamically adjust their reproductive investment in response to the qualities of their mate. In the present study, we show that a lifetime of socially enriched compared with impoverished housing conditions shifts anxiety-like behavior and gene expression of male mice. Females that mate with enriched-reared males exhibit increased levels of pup nursing and licking toward their offspring, which are associated with changes in gene expression within the maternal hypothalamus. Significantly, these changes in maternal behavior are correlated with the general levels of anxiety exhibited by their male mates. Further, we show that paternal environmental enrichment results in increased growth of their offspring. These results suggest that maternal-paternal interactions at mating may guide offspring development, with significant implications for the transgenerational transmission of paternal environmental experiences.

Effects of Cocaine on Maternal Behavior and Neurochemistry

Drug addiction is a chronic relapsing disorder that involves drug seeking and abuse despite the negative social and health consequences. While the potential effects of cocaine on child development have been extensively studied over the last 30 years, few researchers have focused on the effects of cocaine on maternal behavior, which includes offspring care and maternal aggression towards an unfamiliar individual. In humans, maternal cocaine use can lead to child neglect, abuse, and disrupt the mother-child bond. While it has been argued the developmental effects of maternal cocaine use on children were initially overstated, it is clear that disruptions of typical maternal behavior (i.e. postpartum depression, anxiety disorders) are detrimental to the physical and emotional health of offspring. Cocaine use in mothers is commonly associated with psychological disorders, including depression and anxiety, and it is postulated that many of the negative effects of maternal cocaine use on offspring are mediated through changes in maternal behavior. This review will summarize research on cocaine and maternal behavior in animal and human studies, discuss potential mechanisms, and suggest therapeutic strategies for treating cocaine-affected maternal behavior which may improve the physical and behavioral health of both mother and child. The primary objective is to stimulate future communication, cooperation, and collaboration between researchers who use animals and humans to study cocaine and maternal behavior.

Witnessing Violence Toward Siblings: An Understudied but Potent Form of Early Adversity

Research on the consequences of witnessing domestic violence has focused on inter-adult violence and most specifically on violence toward mothers. The potential consequences of witnessing violence to siblings have been almost entirely overlooked. Based on clinical experience we sought to test the hypothesis that witnessing violence toward siblings would be as consequential as witnessing violence toward mothers. The community sample consisted of unmedicated, right-handed, young adults who had siblings (n = 1,412; 62.7% female; 21.8±2.1 years of age). History of witnessing threats or assaults to mothers, fathers and siblings, exposure to parental and sibling verbal abuse and physical abuse, sexual abuse and sociodemographic factors were assessed by self-report. Symptoms of depression, anxiety, somatization, anger-hostility, dissociation and ‘limbic irritability’ were assessed by rating scales. Data were analyzed by multiple regression, with techniques to gauge relative importance; logistic regression to assess adjusted odds ratios for clinically-significant ratings; and random forest regression using conditional trees. Subjects reported witnessing violence to siblings slightly more often than witnessing violence to mothers (22% vs 21%), which overlapped by 51–54%. Witnessing violence toward siblings was associated with significant effects on all ratings. Witnessing violence toward mother was not associated with significant effects on any scale in these models. Measures of the relative importance of witnessing violence to siblings were many fold greater than measures of importance for witnessing violence towards mothers or fathers. Mediation and structural equation models showed that effects of witnessing violence toward mothers or fathers were predominantly indirect and mediated by changes in maternal behavior. The effects of witnessing violence toward siblings were more direct. These findings suggest that greater attention be given to the effects of witnessing aggression toward siblings in studies of domestic violence, abuse and early adversity.

Immediate and enduring effects of neonatal isolation on maternal behavior in rats

Previously, we showed that neonatal isolation (1-hisolation/day from dam, litter, and nest on PND 2–9) facilitates cocaine self-administration and increases extracellular dopamine responses in ventral striatum after stimulant administration in adulthood. Recent studies suggest that enduring alterations in neurobehavioral responses associated with early life manipulations reflect changes in maternal behavior. Thus, we sought to determine if neonatal isolation alters maternal care and if dams with neonatal isolation experience as pups showed differential maternal care towards their pups. In Experiment 1, litters were assigned to one of three conditions: neonatal isolation, handled (5-min separation of dam from litter), or non-handled (no separation). Maternal behaviors were rated on PND 2–9 for 60-min immediately following reunion of mother and litter. In Experiment 2, female rats with or without neonatal isolation experience were assigned to either the neonatal isolation or non-handled litter condition and maternal behaviors rated. Dams of isolated and handled litters spent more time licking pups and less time picking up pups to put outside the nest than dams of non-handled litters. Further, dams of isolated and handled vs. non-handled litters showed less non-maternal behaviors of burrowing and grooming. Neonatal isolation-experienced dams with isolated litters failed to increase pup-licking and decrease non-maternal behaviors. Rather, these dams picked up pups to place outside the nest more than non-handled-experienced dams. Neonatal isolation alters maternal behavior that, in turn, may shape neurobehavioral responses of offspring including effects on maternal care. Such changes may reflect epigenetic effects resulting from changes in maternal behavior.

Association of Substance Use Discussion by Pediatric Providers With the Parent—Provider Relationship and Maternal Behavior Change

A cross-sectional study of data from a randomized, controlled trial was conducted to determine (1) provider and parent attributes associated with discussion of maternal substance use, (2) how substance use discussion related to the parent-provider relationship, and (3) whether discussion was associated with maternal attempts at behavior change. Of the 482 mothers, 34% reported discussing all 3 substance use items (smoking, alcohol, and drug use) with their child's provider. Mothers who discussed smoking were more likely to report discussing alcohol and other drug use (P < .001). Parent-provider relationship scores, measured by a modified version of the Primary Care Assessment Survey, were positively associated with discussion of each substance (P < .001). Discussion of smoking and drug use were significantly associated with attempted behavior change. Our findings suggest that discussion of parental substance use by pediatricians is positively associated with the parent-provider relationship and may lead to behavior change.

Two-Generation Reproductive Toxicity Study of Implanted Depleted Uranium (DU) in CD Rats

Depleted uranium (DU) munitions and armor plating have been used in several conflicts over the last 17 yr, including the Persian Gulf War and the Iraq War. Because of its effectiveness and availability, DU will continue to be used in military applications into the foreseeable future. There is much controversy over the use of DU in weapons and equipment because of its potential radiological and toxic hazards, and there is concern over the chronic adverse health effects of embedded DU shrapnel in war veterans and bystanders. This study evaluated the effects of long-term implantation of DU on the reproductive success of F0 generation adults and development and survival of subsequent F1 and F2 generations in a two-generation reproductive toxicity study. F0 generation Sprague-Dawley rats, 8 wk of age, were surgically implanted with 0, 4, 8, 12, or 20 DU pellets (1 × 2 mm). Inert implant control animals were implanted with 12 or 20 tantallum (Ta) pellets. The F0 generation was then mated at 120 d post DU implantation. In the F0 generation, when measured on postimplantation d 27 and 117, uranium was present in the urine of DU‐implanted animals in a dose-dependent manner. F0 reproductive success was similar across treatment groups and the maternal retrieval test revealed no changes in maternal behavior. DU implantation exerted no effect on the survival, health, or well-being of the F0 generation. Necropsy results of F0 animals were negative with the exception of a marked inflammatory response surrounding the implanted DU pellets. For the F1 generation, measures of F1 development through postnatal day (PND) 20 were unremarkable and no gross abnormalities were observed in F1 offspring. No uranium was detected in whole-body homogenates of PND 4 or PND 20 pups. Necropsy findings of F1 PND 20 pups were negative and no instances of ribcage malformation were observed in F1 PND 20 pups. Body weight and body weight gain of F1 rats through PND 120 were similar across treatment groups. Eight of 414 F1 animals observed from PND 20 to 120 died of unknown causes; 7 were from litters of DU-implanted F0 mating pairs. F1 mating success at 10 wk of age was an overall 70% compared with 91% for F0 mating pairs. Mating success was similar between F1 animals derived from DU-implanted F0 adults and those derived from F0 implant control adults suggesting that the comparatively low mating success was not due to F1 DU exposure. The gestational index of F1 animals derived from mid-dose F0 mating pairs was found to be lower compared with F1 controls. The average gestation duration of F1 animals derived from high-dose F0 mating pairs was found to be significantly longer than F1 controls. F1 sperm motility analyses did not differ among experimental groups and no gross abnormalities were identified at necropsy among surviving F1 animals at PND 120. Histopathology of kidneys, spleen, thymus, bone marrow, ovaries, and testes of F1 high-dose animals did not differ from F1 controls. F1 high-dose females had significantly higher mean relative liver and heart weights compared with F1 controls; the biological relevance of this finding could not be determined. For the F2 generation, measures of F2 development through PND 20 were unremarkable and no gross abnormalities were observed in F2 offspring. Necropsy findings of F2 PND 20 pups were negative and no instances of ribcage malformation were observed in F2 PND 20 pups. Body weight and body weight gain of F2 rats through PND 90 were similar across treatment groups. Mean relative heart weights of males derived from high-dose F0 parents were significantly lower compared with F2 controls. Sperm motility and concentration analysis of F2 males at PND 90 were similar across F2 groups. Overall, the consistent absence of positive findings in this study seems to suggest that DU is not a significant reproductive or developmental hazard, particularly when one considers that mid- and high-dose rats were implanted with the equivalent of 0.3 and 0.5 lb of DU in a 70-kg human, respectively. However, the findings that seven of eight F1 adults that died postweaning were from DU-implanted F0 mating pairs, and that mean relative heart weights were elevated in high-dose F1 and F2 pups, suggest conservatism is warranted in characterizing the reproductive and teratogenic hazards of embedded DU until further studies are completed.