The role of life events in different categories of preterm birth in a group of women with previous poor pregnancy outcome

Childhood Gender Nonconformity and Parental Maltreatment as Mediators of Sexual Orientation Disparities in Childhood Emotional and Behavioral Difficulties

The mechanisms underlying sexual orientation differences in psychopathology originating in childhood remain understudied since sexual orientation does not directly manifest in childhood. This study tested whether childhood gender nonconformity and parental maltreatment before age 6 years 9 months partly explained sexual orientation disparities in the developmental trajectories of emotional and behavioral difficulties from age 6 years 9 months to 11 years 8 months. The Avon Longitudinal Study of Parents and Children was used (2182 boys and 2422 girls, Mage = 15.5, 90% White). After controlling for early life factors, non-heterosexual boys and girls displayed significantly greater emotional and behavioral difficulties than their heterosexual counterparts at all three ages. There was a sex difference in the mediating effects. For girls, sexual orientation disparities in childhood emotional and behavioral difficulties were partially explained by childhood gender nonconformity. For boys, sexual orientation disparities in childhood emotional and behavioral difficulties were partially explained by a path through greater childhood gender nonconformity, leading to increased risk of being the targets of parental maltreatment. Childhood gender nonconformity, parental maltreatment, and other early life factors only partially explain sexual orientation disparities in childhood emotional and behavioral difficulties. The mediating effects of childhood gender nonconformity and parental maltreatment on the association between sexual orientation and childhood emotional and behavioral difficulties differ between the sexes.

The role of mild stressors in children's cognition and inflammation: positive and negative impacts depend on timing of exposure

Although the impact of stressful life events (SLEs) on mental health is well-established, the research on the impact of such stressors on cognitive outcomes has produced mixed results. Arguably, the timing and severity of exposure may play a key role. In this study, we shed light on the relationship between timing of exposure to relatively minor SLEs and cognitive ability in children, while taking into account the role of a plausible biological mediator: inflammation. Using data from the Avon Longitudinal Study of Parents and Children, a general population birth cohort, we explored the role of relatively minor SLEs, experienced during two crucial developmental stages: up to transition to school (1-4.5 years) and up to transition to puberty (5.5-8.5 years). We then tested if they may impact differently on inflammatory markers (serum C-reactive protein [CRP] and interleukin 6 [IL-6]) at age 9 and general intelligence, measured with the Wechsler Abbreviated Scale of Intelligence at age 15. Data (n = 4,525) were analyzed using path analysis while controlling for covariates. We found that when relatively minor stressful events were experienced up to transition to school they were significantly associated with higher IQ at age 15, whereas when experienced up to transition to puberty they were significantly associated with higher levels of IL-6 at age 9. Results were robust to adjustment for relevant covariates, including IQ at age 8. Mild stressors in childhood may result in positive (i.e., improved cognition) or negative (i.e., inflammation) outcomes depending on the timing of exposure.

Internalizing and externalizing problems across childhood and psychotic-like experiences in young-adulthood: The role of developmental period

BACKGROUND

Psychopathology in childhood and adolescence, commonly indexed by co-occurring internalizing and externalizing problem behaviors, has been found to predict psychotic-like experiences (PLEs) in adults. However, studies to date have rarely examined internalizing and externalizing problem behaviors simultaneously or identified in which developmental period do these problem behaviors predict PLEs in adults. This study tests to what extent internalizing and externalizing problem behaviors in childhood (4-9 years) or adolescence (11-16 years) predict PLEs in young-adulthood (18 years).

METHODS

Parent-rated child internalizing and externalizing problems on the Strengths and Difficulties Questionnaire at ages 4, 6, 8, 9, 11, 13, and 16 years from the Avon Longitudinal Study of Parents and Children (N = 4717) were modelled using two-piece latent growth curve modelling to predict clinician-rated PLEs at age 18 years, controlling for confounders (gender, ethnicity, socio-economic status, parental education and stressful life events) assessed prior to baseline at age 4 years.

RESULTS

Controlling for confounders, an increase in childhood internalizing problems from 4 to 9 years and externalizing problems at baseline (at 4 years) predicted PLEs at 18 years, explaining 9.5% of the variance in adult PLEs. These associations were independent to controls for any changes in adolescent internalizing and externalizing problems from 11 to 16 years.

CONCLUSIONS

High baseline levels of externalizing problems and increasing internalizing problems throughout childhood can predict PLEs at 18 years. Externalizing problems around the transition to primary school and internalizing problems throughout childhood may be particularly helpful in informing risk of PLEs in young-adulthood.

Trajectories of internalising and externalising symptoms and inflammation in the general child population

BACKGROUND

Elevations in inflammatory marker levels have been shown to precede internalising and externalising problems in the general child population. One study has found the reverse, that elevations in inflammatory marker levels in childhood follow internalising and externalising problems. However, the authors did not explore the role of the course of these problems in childhood or adjust for a number of potential confounders including psychosocial stressors and prenatal and perinatal exposures.

AIMS

To investigate the association in childhood between the growth of internalising and externalising symptoms and levels of inflammatory markers, while accounting for potential confounders.

METHODS

Using data from the Avon Longitudinal Study of Parents and Children, we tested the association between the trajectories of internalising (emotional and social) and externalising (hyperactivity and conduct) problems, at ages 4, 6, 8 and 9 years, and levels of C-reactive protein (CRP) and interleukin 6 (IL-6) at age 9 years. We analysed data (n = 4525) using latent growth curve modelling and linear regression.

RESULTS

Children who had increasing levels of internalising symptoms over childhood were more likely to have higher levels of CRP and IL-6 at 9 years of age, even after adjustment for confounders. A one-unit increase in the rate of annual change of internalising symptoms was related to an increase of 12% and 8% in the level of CRP and IL-6, respectively. However, there was no evidence for an association between externalising symptoms and either inflammatory marker.

CONCLUSIONS

This study is the first step towards identifying a robust pathway, via increases in emotional and social difficulties, to elevated inflammation in healthy children. This association, if causal, suggests that effective interventions for children experiencing chronic emotional and social difficulties could also have physical health benefits.

Prenatal and childhood adversity and inflammation in children: A population-based longitudinal study

BACKGROUND

Stressful life events experienced during childhood and early prenatal development have been associated with inflammation during childhood. However, no study has considered these two exposures jointly, or has investigated the effect of their interaction.

METHODS

In the Avon Longitudinal Study of Parents and Children, a general-population birth cohort, we explored if inflammatory markers [serum C-reactive protein (CRP) and interleukin 6 (IL-6)] at age 9 years were related to early prenatal events (at 18 weeks pregnancy), childhood events (measured on seven occasions at ages 0-9 years) and their interaction (n = 3,915). Latent growth curve modelling estimated trajectories of childhood events, and linear regression explored associations of prenatal and childhood events with inflammatory markers. Models controlled for ethnicity, socioeconomic status and body mass index, were stratified by gender and considered both unweighted and weighted (by impact) event exposures.

RESULTS

Even after adjustment for confounders and prenatal events, both the intercept and the slope of number of childhood events were associated with IL-6, but only in females. The significant effect of the slope held for both weighted (by impact) and unweighted event specifications. Prenatal events were not associated with either inflammatory marker when childhood events were controlled. There was no evidence for synergistic effects of prenatal and childhood events.

CONCLUSION

Independently of prenatal adverse life events, the number and increase in number of adverse life events experienced in childhood were associated positively with plasma levels of inflammatory markers, such as IL-6, in girls. This gender specificity warrants further research.

Prenatal and childhood adverse life events, inflammation and depressive symptoms across adolescence

BACKGROUND

No study has investigated the role of inflammation in explaining the association between early exposures to adverse life events and depressive symptoms in adolescence.

METHOD

Using data from the Avon Longitudinal Study of Parents and Children, we tested if inflammatory markers [serum C-reactive protein (CRP) and interleukin 6 (IL-6)] at age 9 years mediate the association between adverse life events, measured separately for the prenatal (since the beginning of pregnancy) and the childhood (ages 0-9 years) periods, and the development of depressive symptoms at ages 10-17 years. Data (n = 4,263) were analyzed using mediation analysis in a latent growth curve modeling framework.

RESULTS

Depressive symptoms at the beginning of adolescence (age 10) were associated with the number of prenatal events, the number of events around birth and the increase in events over time in childhood (ages 0-9), even after adjustment for confounders. IL-6 partially mediated the association between increasing exposure to events over time in childhood and depressive symptoms at the beginning of adolescence. IL-6 did not mediate any other association between events and symptoms. There was no evidence for mediation by CRP, which was generally unrelated to exposure to events.

LIMITATIONS

The small size of the mediation effect and the robust direct effects of events prenatally and around birth suggest there are multiple routes from early stressors to adolescent depression.

CONCLUSIONS

In the general adolescent population, increasing exposure to psychosocial stressors over time during childhood is associated with the early onset of depressive symptoms, partly via increasing levels of plasma IL-6.

Childhood Maltreatment, Gender Nonconformity, and Adolescent Sexual Orientation: A Prospective Birth Cohort Study

This study tested whether associations between childhood maltreatment and adolescent sexual orientation were accounted for by childhood gender nonconforming behavior (GNCB) in a prospective birth cohort (N = 5,007). Childhood parental maltreatment (physical and emotional) and GNCB were assessed on multiple occasions up to age 6 years, and sexual orientation at 15.5 years. Boys with a history of maltreatment were significantly more likely to be nonheterosexual. Using propensity score weighting, maltreatment was associated with a 3.5% (p = .03) increase in the prevalence of nonheterosexuality accounting for confounders not including GNCB, and by 2.9% (p = .06) when also accounting for GNCB. These findings suggest that maltreatment is associated with an increased prevalence of nonheterosexuality in boys but may be explained by confounding factors including GNCB.

Stressful life events, inflammation and emotional and behavioural problems in children: A population-based study

OBJECTIVE

To test the hypothesis that higher plasma levels of inflammatory markers due to exposure to adverse life events may lead to internalising and externalising symptoms in children.

METHOD

Using data from the Avon Longitudinal Study of Parents and Children, a general population birth cohort, we explored if inflammatory markers [serum C-reactive protein (CRP) and interleukin-6 (IL-6)] at age 9 years explain the longitudinal association between adverse life events (at ages 1-9 and 9-11 years) and internalising and externalising symptoms (at ages 9 and 11 years). Data (n = 4583) were analysed using cross-lagged panel modelling to take into account reciprocal associations and reverse causality, and path analyses to test for mediation. Gender, ethnicity, body mass index, maternal education, paternal social class and maternal depression were used as potential confounders.

RESULTS

CRP was not associated with adverse life events. There was evidence for partial mediation by IL-6 such that exposure to adverse life events was associated with increased levels of IL-6 later, in turn associated with later internalising symptoms. These associations were robust to adjustment for confounders. IL-6 did not explain part of the opposite association, that of earlier internalising symptoms and later life events, nor did it explain either direction of the association between life events and externalising symptoms.

CONCLUSION

Our findings suggest a pathway that may connect early psychosocial adversity and childhood internalising symptoms via higher plasma levels of inflammatory markers, such as IL-6.

Perinatal Maternal Stress and Susceptibility to Infectious Diseases in Later Childhood: An Early Life Programming Perspective

There is evidence of transmission of stress-related dysregulation from parents to offspring during early developmental stages, leading to adverse health outcomes. This study investigates whether perinatal stress is linked to the risk of infectious diseases in children aged 7-11 years. We hypothesize that stress exposure during pregnancy and the first 6 months after birth independently predict common infectious diseases. Data are obtained from ELSPAC-CZ, a prospective birth cohort. Maternal stress, operationalized as the number of life events, is examined for pregnancy and the first 6 months postpartum. Children's diseases include eye infection, ear infection, bronchitis/lung infection, laryngitis, strep throat, cold sores, and flu/flu-like infection. More prenatal and postnatal life events are both independently linked to a higher number of infectious diseases between the ages of 7-11 years. The effect is larger for postnatal vs. prenatal events, and the effect of prenatal events is attenuated after maternal health in pregnancy is controlled. The results suggest that perinatal stress is linked to susceptibility to infectious diseases in school-age children. Interventions to address stress in pregnant and postpartum women may benefit long-term children's health.

Which children and young people are excluded from school? Findings from a large British birth cohort study, the Avon Longitudinal Study of Parents and Children (ALSPAC)

BACKGROUND

Exclusion from school is increasingly recognized as pertinent to child health. National educational data reveal that boys, children who are looked-after, living in poverty, have special educational needs, or from certain ethnic minorities, are disproportionately excluded from school. As population-based data on the wider characteristics of excluded children are scarce, we aimed to describe predictors of school exclusion in the Avon Longitudinal Study of Parents and Children.

METHOD

Avon Longitudinal Study of Parents and Children, a prospective U.K. population-based birth cohort study, collected parent reports of permanent school exclusions by 8 years and parent and self-reports of permanent and fixed-term exclusions in the preceding 12 months at 16 years. Potential risk factors were examined for associations with exclusion using logistic regression, with a focus on child mental health and neurodevelopment.

RESULTS

Analyses were based on all available data on 53/8,245 (0.6%) pupils excluded from school by 8 years and 390/4,482 (8.7%) at 16 years. Key factors associated with exclusion at both time points included male gender, lower socio-economic status, maternal psychopathology, mental health and behavioural difficulties, psychiatric disorder, social communication difficulties, language difficulties, antisocial activities, bullying/being bulled, lower parental engagement with education, low school engagement, poor relationship with teacher, low educational attainment, and special educational needs (all p < .05).

CONCLUSION

Exclusion from school was associated with child, family and school-related factors identifiable at, or prior to, primary school age. Child health professionals have an important role in the holistic, multidisciplinary assessment of children who are at risk of exclusion from school. Mental health and neurodevelopmental difficulties should be recognized and supported, to improve the health and educational outcomes among this vulnerable group.

Pregnant women with posttraumatic stress disorder and risk of preterm birth

IMPORTANCE

Posttraumatic stress disorder (PTSD) occurs in about 8% of pregnant women. Stressful conditions, including PTSD, are inconsistently linked to preterm birth. Psychotropic treatment has been frequently associated with preterm birth. Identifying whether the psychiatric illness or its treatment is independently associated with preterm birth may help clinicians and patients when making management decisions.

OBJECTIVE

To determine whether a likely diagnosis of PTSD or antidepressant and benzodiazepine treatment during pregnancy is associated with risk of preterm birth. We hypothesized that pregnant women who likely had PTSD and women receiving antidepressant or anxiolytic treatment would be more likely to experience preterm birth.

DESIGN, SETTING, AND PARTICIPANTS

Longitudinal, prospective cohort study of 2654 women who were recruited before 17 completed weeks of pregnancy from 137 obstetrical practices in Connecticut and Western Massachusetts.

EXPOSURES

Posttraumatic stress disorder, major depressive episode, and use of antidepressant and benzodiazepine medications.

MAIN OUTCOMES AND MEASURES

Preterm birth, operationalized as delivery prior to 37 completed weeks of pregnancy. Likely psychiatric diagnoses were generated through administration of the Composite International Diagnostic Interview and the Modified PTSD Symptom Scale. Data on medication use were gathered at each participant interview.

RESULTS

Recursive partitioning analysis showed elevated rates of preterm birth among women with PTSD. A further split of the PTSD node showed high rates for women who met criteria for a major depressive episode, which suggests an interaction between these 2 exposures. Logistic regression analysis confirmed risk for women who likely had both conditions (odds ratio [OR], 4.08 [95% CI, 1.27-13.15]). For each point increase on the Modified PTSD Symptom Scale (range, 0-110), the risk of preterm birth increased by 1% to 2%. The odds of preterm birth are high for women who used a serotonin reuptake inhibitor (OR, 1.55 [95% CI, 1.02-2.36]) and women who used a benzodiazepine medication (OR, 1.99 [95% CI, 0.98-4.03]).

CONCLUSIONS AND RELEVANCE

Women with likely diagnoses of both PTSD and a major depressive episode are at a 4-fold increased risk of preterm birth; this risk is greater than, and independent of, antidepressant and benzodiazepine use and is not simply a function of mood or anxiety symptoms.

Prenatal and early life exposure to stressful life events and risk of autism spectrum disorders: population-based studies in Sweden and England

Background and Aim

Exposure to stressful life events during pregnancy has been suggested as a potential risk factor for offspring Autism Spectrum Disorders (ASD), but the literature is limited and inconsistent. We tested the hypothesis that maternal exposure to stressful life events would be associated with increased risks of offspring ASD, and that these risks would be highest for exposures during the prenatal period.

Methods and Results

We used prospectively collected data from two large population based studies in Sweden and England. In the Swedish study of 4429 ASD cases and 43277 controls, our exposure comprised the occurrence of any severe life event before and during pregnancy and the child's early life. In the English study (maximum n = 11554, ASD n = 72), we studied the risk of offspring ASD in relation to a combined maternal exposure to multiple (up to 42) common and rare life events, as well as their perceived impact upon the mother during pregnancy and early life. In crude and adjusted regression analyses in both studies, we found no evidence of an association between prenatal life events, or their number and perceived impact and the risk of offspring ASD. Sub-group analysis of ASD with and without intellectual disability in the Swedish study yielded similar results.

Conclusion

We found no evidence to support the hypotheses that exposure to stressful life events during the prenatal period is associated with an increased risk of offspring ASD.

Psychosocial stress during pregnancy and perinatal outcomes: a meta-analytic review

The objective of this study was to evaluate the relationship between psychosocial stress in pregnancy and negative perinatal outcomes and to identify key moderators of this relationship. To evaluate this relationship, a meta-analytic review was conducted of studies that prospectively assessed the relationship between psychosocial stress in pregnancy and perinatal outcomes. A total of 35 studies, written or published between 1991 and 2009, involving 31,323 women were located. The overall association between psychosocial stress and negative perinatal outcomes was significant, but negligibly small in size (r (35) = -0.04, CI = -0.08, -0.01). Examining specific perinatal outcomes, only the associations with neonatal weight (r (14) = -0.07, CI = -0.03, -0.01) and risk for low birth weight (r (5) = 0.07, CI = 0.03, 0.10) were statistically significant, but again, very small. Results support that psychosocial stress explains a negligible to very small amount of the variability in perinatal outcomes. Future research should focus on identifying other psychosocial and lifestyle variables that alone or in interaction with other factors explain larger amounts of the variability in perinatal outcomes. Future research should also examine whether psychosocial stress increases risk for negative outcomes in combination with other biomedical and psychosocial risk factors.

Correlates of experiencing life events just before or during pregnancy

This study evaluates the prevalence of selected life events around the time of pregnancy, examining changes in the prevalence of these events, and identifying maternal characteristics associated with these events. We used data from the Pregnancy Risk Assessment Monitoring System (PRAMS) to examine 18 stressful life events among women who recently gave birth and to identify maternal characteristics associated with these events. PRAMS is a mail sample survey with telephone follow-up for non-respondents. Sixty-four percent of women experienced at least one event. The prevalence of specific events ranged from 0.4 to 30%. Women who experienced events differed from those who did not. Most notably, women of low socioeconomic status (SES) were much more likely to experience stressful life events. These events were also associated with other demographic and behavioral characteristics after controlling for SES. These results have implications for interpreting studies of stressful life events. The strong associations with SES highlight the importance of controlling for SES in studies of life events and health, and of considering differences in SES when interpreting these studies.

Stress and preterm delivery: a conceptual framework

Numerous epidemiological studies of various kinds of stress and preterm delivery have produced either negative or weakly positive results. Those inconclusive findings could be either because of the absence of an association or because of recognised methodological problems that may have masked an association. The biological plausibility of the stress hypothesis provides one rationale for continuing stress research, using better study designs. To further this agenda, we propose an epidemiological model, based on the classic "host, environment, agent" triangle of epidemiological causality. The host is the individual woman, more or less susceptible to stressor-induced pathology. The environment includes the social and cultural conditions that are ongoing stressors as well as social and cultural modifiers of stress e.g. those factors that may influence how a particular stressor is experienced or what the physical response to it may be. The agent is the immediate emotional or physical stressor requiring her response. We draw from recent literature, published principally since 1990, to illustrate this model. This epidemiological model posits that whether the individual is overwhelmed by stressors depends not only on the strength of the agents but also upon host susceptibility to stress, as well as the background level of acute, environmental and contextual stressors, and the moderating influence of host, environmental and contextual resources for handling stress. Future research needs to be based on stress hypotheses that include all sides of the triangle, data collection instruments that adequately capture relevant stressors and stress responses, and analytical techniques capable of handling complex, multilevel relationships.

Stress, pre-term labour and birth outcomes

Stress, pre-term labour and birth outcomes Preliminary studies have suggested that stress may be associated with the onset, treatment and outcomes of pre-term labour; however, a systematic comparison of the stress of women with and without pre-term labour has not been reported. Therefore, the purpose of this exploratory study was to compare the stress (daily hassles and mood states) and birth outcomes of black and white women who experienced pre-term labour (PTL) during pregnancy with those who did not. The convenience sample consisted of 35 pregnant women hospitalized in 1996-1997 for the treatment of PTL (24-35 weeks gestation) and 35 controls matched on age, race, parity, gestational age and method of hospital payment. Women in the PTL group had significantly higher tension-anxiety and depression-dejection on the Profile of Mood States (POMS), lower mean birthweight and mean gestational age, and a higher percentage of babies born <37 weeks and weighing 2500 g or less. Black women in the PTL group and white women in the control group had significantly higher scores on the fatigue sub-scale of the POMS and the work and future security sub-scales of the Daily Hassles Scale. Women in the PTL group whose babies weighed 2500 g or less had significantly higher scores on the health, inner concern and financial responsibility sub-scales of the Daily Hassles Scale. The findings from this study indicate the need for further exploration of the interaction of race and stress in understanding and preventing PTL and low birthweight and the need to examine the role of social support in preventing pre-term birth after an episode of PTL.

Maternal stress and obstetric and infant outcomes: epidemiological findings and neuroendocrine mechanisms

This review examines the associations between antenatal maternal stress and obstetric and infant outcomes using preterm delivery as the key outcome indicator. This was done by means of a Medline search focusing predominantly on prospective, controlled studies which investigated both the associated epidemiological factors and putative neuroendocrine mechanisms. There is evidence from a number of United States studies in economically deprived African American women for an association between perceived maternal life event (LE) stress and preterm delivery. The findings from the European studies are conflicting, partly because they combine outcome measures ie. preterm delivery and low birth weight. However the three largest Scandinavian epidemiological studies examining preterm delivery and controlling for confounders such as smoking, age and obstetric history, have confirmed this association. These studies taken together suggest that this may be a robust finding not limited to socioeconomically deprived African American samples and independent of other significant risk factors. Two small prospective studies examining the relationship between the hypothalamic-pituitary-adrenal (HPA) axis, psychosocial status and premature delivery have reported a significant association between a set of adverse psychosocial factors on the one hand, and levels of adrenocorticotrophic hormone (ACTH), corticotrophin releasing hormone (CRH) and cortisol levels, and on the other hand, a significant correlation between CRH levels and premature delivery. Clearly, these findings remain preliminary and indicate a complex relationship between perceived stress in pregnancy, the HPA axis and premature delivery. The impact of antenatal maternal stress on infant temperament and psychopathology remains to be examined more fully in prospective controlled trials.

Stress, social support and pregnancy outcome: a reassessment based on recent research

We present an assessment of studies published in the last decade that consider the relationship of stress and social support to preterm delivery or fetal growth retardation. Included in the review are all reports on the direct effects of stressors or psychological distress; the indirect effects of stressors or distress through health behaviours such as smoking; and the direct and buffering effects of social support. Although an important stimulus for recent stress research has been the attempt to explain racial and social class differences in birth outcome, the recent data show that stressful life events during pregnancy, though more common in disadvantaged groups, do not increase the risk of preterm birth. In contrast, intimate social support from a partner or family member appears to improve fetal growth, even for women with little life stress. Questions unanswered by the research to date are whether elevated levels of depressive symptoms affect pregnancy outcome, either directly or by encouraging negative health behaviours, and whether chronic (vs. acute) stressors are harmful. Additional research is also needed to determine whether psychosocial factors interact with specific clinical conditions to promote adverse pregnancy outcomes. Focusing on intimate support and how it benefits pregnancy outcome could lead to the design of more effective interventions.

Relationship of anxiety, stress, and psychosocial development to reproductive health

In this review of articles on prenatal stress, anxiety, development, and reproductive health outcomes in pregnancy, the focus is on recent research in which the relationships among the major types of stressors, anxiety, and development, on the one hand, and maternal, fetal, and neonatal problems or complications, on the other hand, were examined. Available and effective treatment measures, although limited, are introduced and discussed at length in a follow-up article. Recommendations for policy development based on current research and treatment methods and directions for future research and treatment studies are presented in a third article.