Delivery, Feeding and Gender Differently Contribute to Infant Gut Microbiota Development

To characterize gut microbiome of the infant during the first year of life and assess the different contributions of delivery mode, feeding mode and infant gender to gut microbial development. We collected 314 faecal samples from 80 infants at 5 time points of 0, 1st, 3rd, 6th and 12th months prospectively, and finally 213 samples completed Miseq sequencing and analysis. We characterized gut microbiome of the infant at the different phases and evaluated the different contributions of delivery mode, feeding mode and gender to gut microbial development. Delivery mode, gender and feeding mode were the strongest factors determining gut microbiome colonization at 0 months, from 1 month to 6 months and 12 months, respectively. Four genera including Bifidobacterium, Bacteroides, Parabacteroides and Phascolarctobacterium were increased, whereas 10 genera e.g. Salmonella and Enterobacter were reduced, in vaginal delivery versus cesarean section. Two genera including Peptostreptococcaceae incertae sedis and Anaerococcus were increased, whereas 3 genera e.g. Coriobacteriaceae uncultured were reduced, in exclusive breastfeeding versus combined feeding. This study indicated the contribution degrees of delivery mode, feeding mode and gender to gut microbial initiation and evolvement, and reported microbial differences induced by the different delivery mode, feeding mode and gender.

The Impact of Parental Relationship Satisfaction on Infant Development: Results From the Population-Based Cohort Study DREAM

Extensive literature has shown that interparental conflicts and violence have detrimental effects on children's adjustment in childhood and adolescence. It is not equally well-understood how parental relationship satisfaction impacts infant communicational and personal-social development during the first year of life. This longitudinal study examines (a) the impact of maternal and paternal relationship satisfaction on infant development, (b) whether this prospective association is mediated by parent-infant relationship, and (c) a potential moderating effect of infant gender. Data were derived from the population-based cohort study “Dresden Study on Parenting, Work, and Mental Health” (DREAM) including 1,012 mothers and 676 fathers. Relationship satisfaction and parent-infant relationship were assessed eight weeks postpartum, infant communicational and personal-social development were measured 14 months postpartum. Multiple linear regression, mediation, and moderation analyses were conducted for mothers and fathers separately. It was shown that paternal relationship satisfaction is a significant predictor of infant personal-social development. This prospective association was partially mediated by father-infant relationship. When postnatal depression was included in the analysis, however, father-infant relationship was not a significant mediator. The association in fathers is neither reduced nor increased as a function of infant gender. No similar effects were found in the mothers' sample. Parental relationship satisfaction did not significantly predict infant communicational development in either mothers or fathers. The study findings highlight the importance of paternal relationship satisfaction, father-infant relationship, and postnatal depression for infant personal-social development.

Maternal Serum and Cord Blood Leptin Concentrations at Delivery in Normal Pregnancies and in Pregnancies Complicated by Intrauterine Growth Restriction

Introduction: Leptin is a polypeptide hormone and in pregnancy it is secreted by the placenta and maternal and fetal adipose tissues. The expression of leptin and its specific receptors is observed in the uterine endometrium which indicates leptin involvement in the implantation process and embryonic/fetal development. Normal leptin production is a factor responsible for uncomplicated gestation, embryo development and fetal growth. Objective: To compare at delivery maternal serum and cord blood leptin concentrations in normal pregnancies and in pregnancies complicated by intrauterine growth restriction (IUGR). Material and methods: The study was performed in 25 pregnant women with isolated IUGR diagnosed by ultrasonography (study subjects) and in 194 pregnant women without any comorbid health conditions (controls). Leptin concentrations in maternal serum and in cord blood samples collected at delivery were measured by ELISA and subsequently analyzed by maternal Body Mass Index (BMI), mode of delivery, and infant gender and birth weight. For comparative analyses of normally distributed variables, parametric tests were used, i.e. the Student-t to test the assumption of homogeneity or non-homogeneity of variance and a One-Way ANOVA when more than two groups were compared. The non-parametric Mann-Whitney test was used when the distribution was not normal. The Pearson correlation coefficient was calculated to assess the correlation between normally distributed variables (p<0.05). Results: In pregnancies complicated by IUGR, the mean maternal serum leptin concentration at delivery was significantly higher (52.73 ± 30.49 ng/mL) than in normal pregnancies (37.17 ± 28.07 ng/mL) (p=0.01). The mean cord blood leptin concentration in pregnancies complicated by IUGR was 7.97 ± 4.46 ng/mL and significantly lower than in normal pregnancies (14.78 ± 15.97 ng/mL) (p=0.04). In normal pregnancies, but not in pregnancies complicated by IUGR, a statistically significant correlation was established between maternal serum leptin concentrations and maternal BMI at delivery (r=0,22; p=0.00). No statistically significant correlation was found between cord blood leptin concentrations and maternal BMI in either study subjects or controls. In normal pregnancies, but not in pregnancies complicated by IUGR, a strong correlation was observed between cord blood leptin concentrations and birth weight (r=0,23; p=0.00). In both study subjects and controls, there were no correlations between leptin concentrations in maternal serum and cord blood and infant gender and mode of delivery. Conclusions: Elevated maternal blood leptin concentrations in pregnancies complicated by IUGR may indicate a significant adverse effect of elevated leptin on fetal growth. Enhanced leptin production by the placenta suggests leptin as a candidate marker of placental insufficiency. The differences in leptin concentrations, measured in maternal serum and in cord blood, between the study subjects and controls suggest that deregulated leptin levels may increase the risk of obstetric complications associated with placental insufficiency.

Embodying Gender/sex Identity during Infancy: A Theory and Preliminary Findings

In this paper we tried to loosen the following knot: at somepoint in mid toddlerhood, children evidence a gender/sex—a personal sense of group belonging which alsopredicts individual behaviors and wants—play, dress andpeer preferences. Yet at birth, although individual patterndifferences in embodied responses to new stimuli exist,these do not appear to correlate with gender/sex (Kagan,1994), and few measurable differences exist betweenfemale-designated and male-designated infants. As gender/sex becomes visible and measurable, it already seems toemanate from deep within the body. How does individual—apparently non-gender/sex-correlated-- variability turninto individual gender/sex identity? How do measurablegender/sex-related group differences appear? In this essaywe contrast process-based theories of gender/sex identityand development with theories that posit identity as aninherent trait. From our own research, we offer data thatdemonstrate differences in behavior and infant handlingin mother-son compared to mother-daughter dyads. Weuse these findings and others in the literature to develop atheory of embodiment and conclude with a proposalto refocus research in the field of infant gender/sexdevelopment. Specifically, we urge the use of longitudinal,multi-disciplinary research designs and analytical tools thatemphasize emerging properties and developmental process.

Do emissions from landfill fires affect pregnancy outcomes? A retrospective study after arson at a solid waste facility in Sicily

ObjectivesIn response to public health concern about effects of arson at solid waste management plants in July 2012, we analysed vital statistics data to evaluate any potential effect on pregnancies at different gestational ages of pollutants emitted from the landfill on fire.SettingA community living near the largest landfill plant in Sicily.ParticipantsThe study group comprised 551 births, live births and stillbirths from pregnancies of mothers residing in the extra-urban exposed area, conceived during a 40 week period during which the highest fire’s peak might have influenced pregnancy.Primary and secondary outcome measuresBirth outcomes (gestational age <37 and <32 weeks, low birth weight, very low birth weight and small for gestational age) in the study group were compared with the ones of a reference group of women residing in areas of Sicily with similarly low population density and industrial development.ResultsAmong singleton live births we observed a three-fold increase in risk of very preterm birth between the extra-urban area and the remaining low inhabitants density and unindustrialised areas for births whose pregnancies were in the third trimester (OR adjusted for maternal age and infant gender=3.41; 95% CI 1.04 to 11.16). There was an excess of very low birth weight singleton infants in the study group as compared with the reference group, which was limited to births to mothers exposed during periconception period (OR adjusted for maternal age and infant gender=4.64; 95% CI 1.04 to 20.6) and first trimester (OR adjusted for maternal age and infant gender=3.66; 95% CI 1.11 to 12.1). The association estimates were imprecise due to the small number of outcomes recorded.ConclusionsThe study documented an excess of very preterm and very low birth weight among infants born to mothers exposed to the landfill fire emissions during conception or early pregnancy.

Placental imprinted gene expression mediates the effects of maternal psychosocial stress during pregnancy on fetal growth

Imprinted genes uniquely drive and support fetoplacental growth by controlling the allocation of maternal resources to the fetus and affecting the newborn’s growth. We previously showed that alterations of the placental imprinted gene expression are associated with suboptimal perinatal growth and respond to environmental stimuli including socio-economic determinants. At the same time, maternal psychosocial stress during pregnancy (MPSP) has been shown to affect fetal growth. Here, we set out to test the hypothesis that placental imprinted gene expression mediates the effects of MPSP on fetal growth in a well-characterized birth cohort, the Stress in Pregnancy (SIP) Study. We observed that mothers experiencing high MPSP deliver infants with lower birthweight (P=0.047). Among the 109 imprinted genes tested, we detected panels of placental imprinted gene expression of 23 imprinted genes associated with MPSP and 26 with birthweight. Among these genes, five imprinted genes (CPXM2, glucosidase alpha acid (GAA), GPR1, SH3 and multiple ankyrin repeat domains 2 (SHANK2) and THSD7A) were common to the two panels. In multivariate analyses, controlling for maternal age and education and gestational age at birth and infant gender, two genes, GAA and SHANK2, each showed a 22% mediation of MPSP on fetal growth. These data provide new insights into the role that imprinted genes play in translating the maternal stress message into a fetoplacental growth pattern.

Longitudinal Variation of Amino Acid Levels in Human Milk and Their Associations with Infant Gender

It is discussed that specific amino acids (AAs) have functional roles in early life. Understanding the AA composition in human milk (HM) during lactation assists in specifying these roles. To this end we assessed the levels of free AAs (FAAs), total AAs (free and bound, TAAs) and protein levels in HM in the first 6 months of lactation, and evaluated possible associations with infant gender. HM samples of 25 healthy Dutch mothers participating in the PreventCD study were collected monthly during the first 6 months of lactation. Of the participating mothers, 12 gave birth to a boy and 13 gave birth to a girl. Analyses of the HM samples revealed that levels of free glutamate, glutamine, aspartate, glycine, and serine significantly increased during months 1–3 of lactation, both in absolute sense and relative to TAA levels. Evaluation of gender differences by mixed model analyses revealed an association between female infant gender and higher protein content (p = 0.0465) and TAA content (p = 0.0362) in HM during the first 3 months of lactation. Furthermore, there was a tendency for an association of male infant gender with higher levels of free glutamine (p = 0.0948) in HM during the first 3 months of lactation. These results show that FAA, TAA and protein levels in HM display a time-specific occurrence during lactation. Moreover, although confirmation is necessary in view of the small sample size, this study indicates that the AA composition in HM shows differential effects of the infant’s sex.

U.S. and Chilean Mothers’ Use of Mental References With Infant Girls and Boys: Comparison of Maternal Practices in Gender Socialization via Language in Two Countries

Variability in parents’ socialization of gender across countries has been understudied. To address the gap, this study compares U.S. and Chilean mothers’ practices in socialization of gender through use of mental state language. Drawing on 90 Chilean and 52 U.S. mother–infant dyads, we examined variation in the frequencies of mothers’ utterances of five types of mental references—emotion, desire, physiological states, causal talk, and cognition—to determine whether they varied by country and infant gender. Infant age ranged between 10 and 15 months. The frequencies with which both U.S. and Chilean mothers in our sample talked about most mental references did not vary according to infant gender, with the exceptions of causal talk in the United States. Specifically, the U.S. mothers used more causal talk with girls than boys. There were more similarities than differences in maternal use of the mental references in the U.S. and Chilean samples. This study did not observe gendered socialization practices through the use of these mental references in infancy among the U.S. and Chilean mothers. Instead, the current study suggests that, using mothers’ mental references in the child’s first year as the indicator, both gender-neutral and cross-gendered socialization practices emerge in the United States, and only gender-neutral socialization practices emerge in Chile.