The relation of maternal job strain and cortisol levels during early pregnancy with body composition later in the 5-year-old child: the ABCD study

Background

Prenatal exposure to maternal stress may program the fetal HPA axis, potentially leading to altered metabolism in later life, associated with adiposity and diabetes.

Aims

This association is little studied in humans, and thus we explore whether high maternal job strain during early pregnancy, as well as maternal cortisol levels are associated with increased body mass index (BMI), central adiposity or body fat mass in the offspring at age five. Additionally, we explore whether these associations are modified by gender or mediated by gestational age and fetal growth restriction.

Study design

2939 pregnant women (ABCD cohort study) completed a questionnaire around gestational week 16 including the Job Content Questionnaire, assessing job strain. Serum total cortisol was assessed in a subsample (n = 1320). Gestational age (≥ 37 weeks), standardized birth weight and information on many covariates were available. At the age five health check, height, weight (BMI, kg/m²), waist circumference (waist-to-height ratio, WHtR) and Fat Mass Index (FMI, kg/m²) were assessed.

Results

Job strain was not associated with higher BMI, WHtR or FMI. Higher maternal cortisol was independently associated with marginally higher FMI in girls, but marginally lower FMI in boys (β 0.09 and β −0.10 per 100 unit increase in serum cortisol, respectively. p < 0.01). This association was not mediated by gestational age or fetal growth restriction.

Conclusions

Results show that prenatal maternal job strain and cortisol may not program obesity and adiposity in the next generation in humans, but gender differences should always be considered.     

Effect of holding on co-regulation in preterm infants: A randomized controlled trial

Objective

To determine whether kangaroo holding of healthy preterm infants over the first eight weeks of an infant's life facilitates co-regulation of salivary cortisol between mother and infant.

Study Design

Randomized control trial. Infants were assigned to receive 1 h of daily kangaroo (skin-to-skin contact on the chest of mother) or blanket holding (dressed and held in mother's arms). A registered nurse visited mothers weekly for eight weeks to encourage holding and provide information about infant development. A control group had no holding restrictions and received weekly brief social visits.

Subjects

The study included 79 preterm infants, born between 32 and 35 weeks gestational age and were a mean of 15 days (± 5.7) at enrollment.

Outcome Measures

Co-regulation was conceptualized as progressive reduction in the absolute difference between mother and infant cortisol levels across 60 min of holding at each holding session. Mother and infant cortisol levels were measured before holding and at 30 and 60 min after holding began during three holding sessions (baseline and at two and eight weeks after study initiation). Primary analyses were conducted using hierarchical linear models.

Results

There was much variability in cortisol levels. Levels of mother and infant cortisol decreased during holding. No significant co-regulation occurred in any group at any holding session or over time.

Conclusions

Decreasing level of cortisol in both mothers and infants suggests that holding promoted the expected decline in stress hormone levels. However, supported holding methods did not differentially affect co-regulation compared to controls. Holding is pleasurable and stress may need to be present in order for mothers and infants to demonstrate co-regulation in cortisol levels.     

Work/non-workday differences in mother,child, and mother–child morning cortisol in a sample of working mothers and their children

Background

Mothers have been shown to have higher morning cortisol on days they go to work compared to non-workdays; however, it is unknown how maternal workday associates with child morning cortisol or the attunement of mother–child morning cortisol.

Aims

This study examined the presence and stability of morning cortisol levels and slopes (i.e., cortisol awakening response or CAR) in a sample of 2–4 year old children in out-of-home child care with working mothers. In addition, we examined the differential contributions of maternal workday on mother–child attunement in morning cortisol.

Method

Mother and child morning cortisol was sampled twice a day (awakening and 30 min later) across four consecutive days (2 non-workdays; 2 workdays) among 47 working mothers and their young children. Mothers also reported on compliance with sampling procedures and provided demographic information.

Results

While children exhibited stability in cortisol levels, children's CARs were variable, with children's non-work CARs not predictive of work CARs. Similarly, a significant morning rise in cortisol was only found on workdays, not non-workdays. Overall, mothers had higher cortisol levels and steeper CARs than their children. Further, maternal workday moderated the attunement of mother–child morning cortisol, such that mothers and children had concordant cortisol levels on non-workdays, but discordant cortisol levels on workdays.

Conclusions

Morning cortisol may be more variable in pre-school aged children than adults but may be similarly responsive to the social environment. Further, workday mornings may be a time of reduced mother–child cortisol attunement.     

Parenting self-efficacy: Links with maternal depression,infant behaviour and adult attachment

Background

This study examined predictors of parenting self-efficacy (PSE) in a sample of first-time mothers during the first year after childbirth and evaluated the effect of a brief, intensive, mother–infant residential intervention on PSE and infant behaviour.

Methods

83 primiparous women with infants aged 0–12 months admitted to a residential parent–infant program participated in a structured clinical interview for DSM-IV diagnosis of depressive and anxiety disorders and completed questionnaires assessing psychological distress, adult attachment and childhood parenting experiences. During their residential stay, nurses recorded infant behaviour using 24-hour charts.

Results

Results showed PSE to be inversely correlated with maternal depression, maternal anxiety and attachment insecurity. Low levels of parental abuse during childhood, avoidant attachment, male infant gender and depressive symptom severity were found to predict low PSE. Major depression mediated the relation between attachment insecurity and PSE, but there were no links between PSE and infant behaviour. After the intervention, there was a significant improvement in PSE, with abusive parenting during childhood and depressive symptom severity being predictive of change.

Conclusions

This study highlights the links between maternal psychopathology and maternal background factors such as childhood parenting experiences and attachment style in the development of postnatal PSE. Directions for future research are discussed.     

Maternal emotional availability at bedtime and infant cortisol at 1 and 3 months

Background

Previous work has shown that early experience influences infant cortisol secretion. Few studies, however, have examined associations between parenting quality and cortisol levels and patterning in very young infants.

Aims

This study examined linkages between maternal emotional availability (EA) during a routine caregiving task, bedtime, and infant cortisol in the first 3 months of life. Concurrent and longitudinal associations between maternal EA and infant cortisol were examined.

Study design

Families were visited when their infants were 1 and 3 months old. Video equipment was set up in order to record the infant's bedtime routine. Parents were provided with materials with which to take saliva samples from their infants at late afternoon, bedtime, and the following morning.

Subjects

At 1 month, participants were 96 mothers and infants living in a rural U.S. state. Data were available for 88 mothers and infants at 3 months.

Outcome measures

Maternal EA was scored from videotapes of bedtime at each age point. Infant cortisol was assessed from the saliva samples taken by parents.

Results

Regression analyses indicated that at 1 and 3 months of age, infants of more emotionally available mothers showed lower levels of cortisol secretion across the night than infants of less emotionally available mothers. Additionally, multilevel model analyses indicated that infants of more emotionally available mothers showed greater evidence of a decline in their cortisol levels across the evening, followed by an increase across the nighttime into the morning in their cortisol at 3 months.

Conclusions

Findings suggest that maternal care in the context of a routine caregiving task is associated with lower stress reactivity and with earlier circadian patterning in very young infants.     

Postnatal depression mediates the relationship between infant and maternal sleep disruption and family dysfunction

Background

Previous research has linked family sleep disruption and dysfunction in children; however, the mechanism is unknown.

Aims

This study examined whether maternal sleep and postnatal depression (PND) mediate the relationship between infant sleep disruption and family dysfunction.

Study design and participants

Mothers of infants aged 12 months old (N = 111; 48% male) completed infant and parent sleep surveys, the Edinburgh Postnatal Depression Scale and the Family Assessment Device.

Results

Poor infant sleep was related to poor maternal sleep, which was associated with higher PND and higher level of family dysfunction.

Conclusions

Results are consistent with the proposition that identification of both infant and maternal sleep problems during infancy can be relevant to reduction of PND and improved family functioning.     

Infant developmental outcomes following prenatal exposure to antidepressants,and maternal depressed mood and positive affect

Background

Prenatal exposure to serotonin reuptake inhibitor (SRI) antidepressants has been associated with delays in early developmental milestones, but there remains uncertainty. Even among a subset of studies examining the Bayley Scales of Infant Development (BSID), some have reported normal mental and psychomotor development while others have suggested a delay in motor development. Given an increasing number of infants exposed to SRIs, furthering our understanding of the possible developmental implications of SRI exposure in utero is critical.

Aims

To examine the effects of prenatal serotonin reuptake inhibitor exposure and maternal mood on infant developmental outcomes at 10 months of age.

Study design

Prospective study of mothers and their 10-month-old infants.

Subjects

We examined 31 mother–child pairs exposed prenatally to SRIs and 52 mother–child pairs who were nonexposed.

Outcome measure

The Bayley Scales of Infant Development (third edition) scores.

Results

Infants exposed prenatally to SRIs scored significantly lower than nonexposed infants on gross motor (P = 0.03), social–emotional (P = 0.04) and adaptive behavior (P = 0.05) subscales of the BSID-III, controlling for pre- and postnatal maternal depressed mood, smoking and alcohol use during pregnancy. No significant differences in any of the BSID-III subscales were observed between infants exposed and infants nonexposed to pre and postnatal maternal depressed mood (P > 0.05). Increased levels of maternal positive affect at 10 months predicted increased social–emotional scores (P = 0.03).

Conclusions

Infants prenatally exposed to SRIs score significantly lower on the gross motor, social–emotional and adaptive behavior subscales of the BSID-III, and this was not explained by underlying maternal depression.     

Hypothalamic-pituitary-adrenal (HPA) axis function in 3-month old infants with prenatal selective serotonin reuptake inhibitor (SSRI) antidepressant exposure

Background

Prenatal exposure to stress and selective serotonin reuptake inhibitors (SSRIs) alter hypothalamic-pituitary-adrenal (HPA) stress reactivity in offspring, however, the effects of combined exposure to HPA activity in human infants is unknown.

Objective

To examine HPA basal levels and stress responsiveness in 3-month olds with prenatal exposure to SSRIs.

Methods

Salivary cortisol levels in infants of SSRI treated mothers (n = 31, mean exposure 230.2 ± 72.2 days) were compared with non-SSRI exposed (n = 45) infants in response to a challenge (infant-controlled habituation task) and under basal conditions in the late afternoon/early evening. Mode of feeding, to account for possible postnatal drug exposure via breast milk, as well as measures of pre and postnatal maternal mood, were included as covariates.

Results

Lower post-stress cortisol levels were observed in non-SSRI exposed/non-breastfed infants compared with non-SSRI exposed infants who were breastfed at 3 months of age. Stress reactivity patterns among SSRI exposed infants did not differ with mode of feeding. The cortisol reactivity slope (CRS) was significantly lower among non-SSRI exposed non-breastfed infants compared with non-SSRI exposed breastfed infants. Early evening basal cortisol levels were lower in SSRI exposed infants than in non-SSRI exposed infants, controlling for maternal mood and mode of feeding. Postnatal SSRI exposure (infant SSRI drug levels) via breast milk was not associated with stress or basal cortisol levels. Total cortisol, reflected by the AUC measure, did not differ significantly between exposure groups.

Conclusions

Prenatal SSRI exposure altered HPA stress response patterns and reduced early evening basal cortisol levels. Stress challenge HPA response differences only became apparent when the moderating effect of method of feeding was accounted for. These findings suggest an early “programming” effect of antenatal maternal mood, prenatal SSRI exposure and postnatal maternal care giving on the HPA system.     

Comparison of fetal heart rate patterns using nonlinear dynamics in breech versus cephalic presentation at term

Background

It has been reported that breech fetuses have inferior neurological outcomes regardless of mode of delivery, raising the possibility that in utero neurological impairment is more frequent in breech fetuses, possibly contributing to malpresentation.

Aims

To assess differences between the cardiovascular autonomic nervous systems (ANSs) of breech and cephalic fetuses using nonlinear dynamic indices of fetal heart rate (FHR) variability.

Study design and subjects

This study included 86 fetuses with breech presentation and 173 fetuses with cephalic presentation, with no other maternal or fetal problems. We analyzed FHR variability and spectral indices as markers of ANS behavior. We used nonlinear dynamic indices to represent the complexity of heart rate regulation, as well as correlation dimension as a chaotic index of the cardiovascular control system.

Results

One of FHR parameters (Mean minute range) was significantly lower in breech than cephalic fetuses (p = 0.0294). However, there were no other significant differences in any linear or nonlinear indices, nor in clinical outcomes, between breech and cephalic fetuses.

Conclusion

Our data suggest that breech fetuses have neither more active ANS nor less active complexity control systems than do cephalic fetuses. This indicates that the neurologic maturation of breech fetuses is not inferior to cephalic ones. The practical implication of these findings is that the nervous system integrity of breech fetuses may not result directly in neonatal complications.     

Maternal diet and breastfeeding: a case for rethinking physiological explanations for breastfeeding determinants

Background

Although some authors explain determinants of breastfeeding that occur in a dose–response manner as evidence of causality, we argue that dose–response relationships are not proof of a biological relationship between the variables. The relationship between maternal smoking and breastfeeding and maternal obesity and breastfeeding are similar: increasing levels of smoking or obesity are associated with shorter duration of breastfeeding. However, maternal infant feeding intention is a strong predictor of breastfeeding duration.

Aims

In this paper we present data on another variable with a clear dose–response relationship with breastfeeding duration – maternal diet – as a case study to argue that a dose–response relationship does not imply causality.

Study design

Secondary analysis of cross-sectional survey.

Subjects

Nationally representative sample of 3544 singleton infants in Longitudinal Study of Australian Children, 2004.

Outcome measures

Maternal intake of fruit and vegetables; breastfeeding duration.

Results

Adjusted Odds Ratios (AOR) for breastfeeding at 6 months for daily maternal fruit and vegetable intake (reference group = no fruit/vegetables): 1 serve AOR 1.6 (95%CI 1.0, 2.6); 2 serves AOR 2.3 (1.5, 3.5); and 6 or more serves AOR 4.4 (2.8, 6.8).

Conclusions

Although higher maternal intake of fruit/vegetables is associated with longer breastfeeding duration, this is not a biological causal relationship. There are possible biological explanations for altered milk supply in women who smoke or are obese, but not for fruit/vegetable intake. We call for a broader understanding of the social determinants of infant feeding and suggest that all breastfeeding studies measure maternal infant feeding intention as an important determinant.     

The relation of infant attachment to attachment and cognitive and behavioural outcomes in early childhood

Background

In China, research on the relation of mother–infant attachment to children's development is scarce.

Aims

This study sought to investigate the relation of mother–infant attachment to attachment, cognitive and behavioural development in young children.

Study design

This study used a longitudinal study design.

Subjects

The subjects included healthy infants (n = 160) aged 12 to 18 months.

Outcome measures

Ainsworth's “Strange Situation Procedure” was used to evaluate mother–infant attachment types. The attachment Q-set (AQS) was used to evaluate the attachment between young children and their mothers. The Bayley scale of infant development-second edition (BSID-II) was used to evaluate cognitive developmental level in early childhood. Achenbach's child behaviour checklist (CBCL) for 2- to 3-year-olds was used to investigate behavioural problems.

Results

In total, 118 young children (73.8%) completed the follow-up; 89.7% of infants with secure attachment and 85.0% of infants with insecure attachment still demonstrated this type of attachment in early childhood (κ = 0.738, p < 0.05). Infants with insecure attachment collectively exhibited a significantly lower mental development index (MDI) in early childhood than did infants with secure attachment, especially the resistant type. In addition, resistant infants were reported to have greater social withdrawal, sleep problems and aggressive behaviour in early childhood.

Conclusion

There is a high consistency in attachment development from infancy to early childhood. Secure mother–infant attachment predicts a better cognitive and behavioural outcome; whereas insecure attachment, especially the resistant attachment, may lead to a lower cognitive level and greater behavioural problems in early childhood.     

Parental psychological distress during pregnancy and childhood cardiovascular development. The Generation R Study

Background

Maternal psychological distress during pregnancy might lead to higher fetal cortisol exposure, which subsequently leads to fetal cardiovascular developmental adaptations and cardiovascular dysfunction in later life.

Aims

We examined whether maternal and paternal psychological distress was associated with the cardiovascular outcome measurements in school age children.

Study design and subjects

In a population-based prospective cohort study among 4831 children, we assessed maternal and paternal psychological distress during pregnancy by questionnaire, using the Brief Symptom Inventory (see Fig. 1).

Outcome measures

At the child age of six years, we performed blood pressure and carotid–femoral pulse wave velocity measurements, and M-mode measurements of left cardiac structures and fractional shortening.

Results

We did not observe associations of high maternal and paternal psychological symptom scores with childhood blood pressure and carotid–femoral pulse wave velocity after adjustment for potential confounders. Maternal overall psychological symptoms were associated with a lower childhood left ventricular mass (difference − 1.10 g (95% confidence interval − 2.13 to − 0.07) between mothers with high scores and normal scores), but not with other cardiac structures and fractional shortening. Paternal overall psychological symptoms showed a similar association with childhood left ventricular mass (difference − 1.34 grams (95% confidence interval − 3.69 to 1.02) between fathers with high scores and normal scores).

Conclusions

Our results do not support the hypothesis that maternal psychological distress affects cardiovascular development in early life. Similar associations of maternal and paternal psychological distress with left ventricular mass suggest that these associations could be due to unmeasured social and environmental factors, rather than direct intra-uterine effects.     

Heart rate variability during caregiving and sleep after massage therapy in preterm infants

Background

Preterm birth impairs the infant's stress response due to interruption of autonomic nervous system (ANS) development. Preterm infants demonstrate a prolonged and aberrant sympathetic response to stressors. ANS development may be promoted by massage therapy (MT), which has been shown to improve stress response in preterm infants.

Aims

The aim of this study was to compare preterm infant ANS function and stress response during sleep and caregiving epochs, as measured by heart rate variability (HRV), after two weeks of twice-daily MT.

Study design

A subset of participants from a larger randomized, masked, controlled trial was used.

Subjects

Twenty-one infants (8 males and 13 females) from a larger study of 37 medically stable preterm infants were studied. The infants were receiving full volume enteral feedings with a mean post-menstrual age of 31.4 (MT) and 30.9 (control) weeks.

Outcome measures

Low to high frequency (LF:HF) ratio of HRV was the outcome of interest.

Results

There was a significant group × time × sex interaction effect (p < .05). Male control infants demonstrated a significant decline in LF:HF ratio from baseline to the second caregiving epoch, suggesting decreased mobilization of sympathetic nervous system response when exposed to stressors. Male MT infants demonstrated increased LF:HF ratio during caregiving and decreased LF:HF ratio during sleep epochs, suggesting improved ANS function, although this was not statistically significant. LF:HF ratio was similar in female MT and female control infants during caregiving and sleep.

Conclusions

Control males had decreased HRV compared to MT males. There was no difference in HRV between MT and control females.     

Preterm birth and Assisted Reproductive Technology/ART: maternal emotional wellbeing and quality of mother-newborn interaction during the first three months of life

Objective

Assisted Reproductive Technology (ART) and premature birth are stressful and difficult experiences for women. No research to date has examined the impact of ART on mother–child relationship in instances of preterm delivery. This study explored the psychological status of preterm infants' ART-mothers and the quality of mother–infant dyadic interaction, up to child age of three months (Corrected Age = CA).

Method

Forty-one ART-dyads and 53 Spontaneous Pregnancy (SP) dyads were enrolled. Mother and child were assessed at 5 to 7 days after birth (T1), at child discharge from hospital (T2), at one month after discharge (T3); and at 3 months CA (T4). The following measures were administered to the mothers: the Gordon Personal Profile Inventory, the Beck Anxiety Inventory, the Beck Depression Inventory, and the Parenting Stress Index S–F. Mother–child interaction was coded by using the Nursing Child Assessment Feeding Scale.

Results

At childbirth, the control group mothers showed a higher level of anxiety than the ART-mothers did, but at T2, T3, T4, both groups' parenting stress levels were below threshold. Conversely, ART mothers more frequently provided suitable stimulation for their child's socio-emotional and cognitive development than the control group did. No significant between-group differences were observed in the mothers' capacity to respond to their children's distress, nor in sensitivity to child cues. Both infant groups showed equal ability to send clear signals and to respond to parent-provided care.

Conclusions

ART and SP mothers with premature infants showed no differences in degree of emotional burden experienced during the neonatal period. Yet, dyadic interaction was qualitatively better in ART dyads than in SP dyads.     

Differential associations between maternal scaffolding and toddler emotion regulation in toddlers born preterm and full term

Background

Parental “scaffolding” behavior has been associated with developmental outcomes in at-risk children.

Aims

Because there are limited empirical data regarding how scaffolding is associated with emotion-based developmental skills, the purpose of this study was to compare associations between maternal verbal scaffolding and toddler emotion regulation, including fewer displays of negative affect and increased contentment and enjoyment during play, in toddlers born preterm and full term.

Study design

This study was a cross-sectional cohort design. Maternal and toddler behavior was assessed during 5 min of videotaped free play with standardized toys.

Subjects

131 toddlers (18–22 months) and their mothers were included (77 born preterm; 54 born full term).

Outcome measures

Toddler emotion regulation, negative affect, and dyadic mutual enjoyment were coded from videotaped play.

Results

The association between maternal scaffolding and emotion regulation was different for dyads with a toddler born preterm versus full term, wherein the association was positive for toddlers born preterm and non-significant for toddlers born full term. Similarly, the association between maternal scaffolding and negative affect was different for the two groups: negative for toddlers born preterm and non-significant for toddlers born full term. Finally, the association between maternal scaffolding and mutual enjoyment was positive for toddlers born preterm and non-significant for toddlers born full term.

Conclusions

Our findings highlight early differences in mother-child interactive style correlates of children born preterm compared to those born full term. Maternal scaffolding behavior may be uniquely associated with emotion regulation and a positive dyadic encounter for toddlers born preterm.     

Development of a scale for estimating procedural distress in the newborn intensive care unit: The Procedural Load Index

Background

Infants in the newborn intensive care unit (NICU) are exposed to routine procedures that often cause distress and carry a negative burden or load on the infant's neurodevelopment.

Aim

A ratio level index is introduced to estimate procedural load so as to begin to develop a system to monitor the intensity of distress associated with common NICU procedures.

Study design

Two psychophysical methods, magnitude estimation (ME) and the general labeled magnitude scale (gLMS) were used to survey 86 clinicians via the internet to estimate the distress associated with 55 common NICU procedures.

Results

gLMS and ME estimations correlated highly across all procedures (r = 0.97). gLMS values were used to derive the procedural load index (PLI) as a ratio level estimation of procedural distress.

Conclusion

The PLI ranks and differentiates distress among common NICU procedures more precisely than current tools. This methodology, if correlated with infant physiological indices and health outcomes, may be operationalized at the bedside to measure procedural distress, and help to guide the ideal timing to perform procedures and minimize their negative consequence.     

Child and environmental factors associated with leisure participation in adolescents born extremely preterm

Background

Developmental impairments persist among adolescents born extremely preterm, and these individuals are at an increased risk for chronic disease later in life. Participating in active and positive leisure activities may act as a buffer against negative outcomes, but involvement in active-physical and skill-based activities is low in youth born preterm.

Aims

To explore the child and environmental determinants of leisure participation among adolescents born extremely preterm.

Study design

Cross-sectional study.

Subjects

Participants were recruited from the hospital's Neonatal Follow-Up Program and included 128 adolescents born preterm (mean gestational age: 26.5 weeks).

Outcome measures

Leisure participation was assessed using the Children's Assessment of Participation and Enjoyment. Potential determinants were assessed using standardized tests and questionnaires. Selected factors were entered into five separate multivariable regression models.

Results

Child and environmental factors contributed between 21% (skill-based) and 52% (active physical) of the adjusted variance for participation intensity. Lower gestational age was associated with greater participation in recreational activities. Male sex, higher maternal education and better motor competence were associated with involvement in active-physical activities. Being older and feeling socially accepted were associated with participation in social activities. Families oriented to hobbies and higher maternal education were associated with participation in skill-based activities. Preference was the strongest determinant of participation in all five leisure activities.

Conclusions

Activities should be adapted to individual skill level, include family and peers, foster social acceptance and be driven by the adolescent's preferences. Although certain factors cannot be modified, they can be used to identify adolescents at risk for low participation.     

Aerobic exercise during pregnancy influences infant heart rate variability at one month of age

Background

Previously, we reported that regular maternal aerobic exercise during pregnancy was associated with lower fetal heart rate (HR) and higher heart rate variability (HRV) at 36 weeks gestation. We now report the effect of maternal exercise on infant HR and HRV in subjects who remained active in the study at the one-month follow up visit.

Aims

We aimed to determine whether differences in fetal cardiac autonomic control related to maternal physical activity were an in utero phenomenon or would persist 1 month after birth.

Study design

Magnetocardiograms (MCGs) of infants born to regularly exercising (≥ 30 min of aerobic activity, 3 times per week; N = 16) and non-exercising (N = 27) pregnant women were recorded using a fetal biomagnetometer. Normal R-peaks were marked to derive infant HR and HRV in time and frequency domains, including the root mean square of successive differences (RMSSD), the standard deviation of normal-to-normal interbeat intervals (SDNN), and power in the low frequency (LF) and high frequency (HF) bands. Group differences were examined with Student's t-tests.

Results

Infants born to exercising women had significantly higher RMSSD (P = 0.010), LF power (P = 0.002), and HF power (P = 0.004) than those born to women who did not engage in regular physical activity while pregnant.

Conclusion

Infants born to women who participated in regular physical activity during pregnancy continued to have higher HRV in the infant period. This suggests that the developing cardiac autonomic nervous system is sensitive to the effects of maternal physical activity and is a target for fetal programming.     

Cord blood 8-isoprostane in the preterm infant

Background

Cord blood 8-isoprostane (8-IP) is a marker of lipid peroxidation in the peripartum period. The independent association with degree of prematurity is not well-described.

Objective

To identify patterns of lipid peroxidation among early, moderate and late preterm infants, and to understand how cord blood 8-IP varies with gestational age (GA) and related covariates.

Study design

Mother–infant pairs from 237 preterm births were studied as part of a longitudinal birth cohort study. GA subgroups were defined as extremely (≤ 28w), moderately (29–33w), and late (34–36w) preterm. Cord blood 8-IP was measured using EIA. Elevated 8-IP (4th quartile) was the primary outcome for multivariate logistic regression models, which were adjusted for maternal age/race, multiple gestation and infant gender, as well as other relevant covariates.

Results

Elevated 8-IP was associated with extremely preterm birth (OR = 4.31; 95% CI = 1.90, 9.76), and was inversely associated with increasing GA (OR = 0.88; 95% CI = 0.80, 0.97). Elevated 8-IP was also associated with decreasing birth weight (BW), clinical chorioamnionitis, fetal inflammatory response of the placenta (FIR), and signs of perinatal depression. The GA on 8-IP association appeared to be modified by several maternal disease and fetal–infant factors. Lastly, the indirect associations between log-transformed 8-IP, GA and BW appeared to be most prominent for GA < 30w and for BW < 2000 g.

Conclusion

Lipid peroxidation in preterm birth, and the relative influence of accompanying peripartum factors, varies according to degree of prematurity. These findings have important implications for the developmental regulation of antioxidant defense and its impact on neonatal outcomes.