Christine Dunkel Schetter

Psychological Science on Pregnancy: Stress Processes, Biopsychosocial Models, and Emerging Research Issues

Psychological science on pregnancy is advancing rapidly. A major focus concerns stress processes in pregnancy and effects on preterm birth and low birth weight. The current evidence points to pregnancy anxiety as a key risk factor in the etiology of preterm birth, and chronic stress and depression in the etiology of low birth weight. Key mediating processes to which these effects are attributed, that is neuroendocrine, inflammatory, and behavioral mechanisms, are examined briefly and research on coping with stress in pregnancy is examined. Evidence regarding social support and birth weight is also reviewed with attention to research gaps regarding mechanisms, partner relationships, and cultural influences. The neurodevelopmental consequences of prenatal stress are highlighted, and resilience resources among pregnant women are conceptualized. Finally, a multilevel theoretical approach for the study of pregnancy anxiety and preterm birth is presented to stimulate future research.

Anxiety, depression and stress in pregnancy: implications for mothers, children, research, and practice.

Purpose of review To briefly review results of the latest research on the contributions of depression, anxiety, and stress exposures in pregnancy to adverse maternal and child outcomes, and to direct attention to new findings on pregnancy anxiety, a potent maternal risk factor. Recent findings Anxiety, depression, and stress in pregnancy are risk factors for adverse outcomes for mothers and children. Anxiety in pregnancy is associated with shorter gestation and has adverse implications for fetal neurodevelopment and child outcomes. Anxiety about a particular pregnancy is especially potent. Chronic strain, exposure to racism, and depressive symptoms in mothers during pregnancy are associated with lower birth weight infants with consequences for infant development. These distinguishable risk factors and related pathways to distinct birth outcomes merit further investigation. Summary This body of evidence, and the developing consensus regarding biological and behavioral mechanisms, sets the stage for a next era of psychiatric and collaborative interdisciplinary research on pregnancy to reduce the burden of maternal stress, depression, and anxiety in the perinatal period. It is critical to identify the signs, symptoms, and diagnostic thresholds that warrant prenatal intervention and to develop efficient, effective and ecologically valid screening and intervention strategies to be used widely.

Elevated maternal cortisol early in pregnancy predicts third trimester levels of placental corticotropin releasing hormone (CRH): Priming the placental clock

The purposes of this study were to determine the intervals when placental corticotrophic-releasing hormone (CRH) was most responsive to maternal cortisol. A sample of 203 women each were evaluated at 15, 19, 25 and 31 weeks gestation and followed to term. Placental CRH and maternal adrenocorticotropin hormone (ACTH), B-endorphin and cortisol were determined from plasma. CRH levels increased faster and were higher in women who delivered preterm compared with women who delivered at term (F3,603 = 5.73, p < .001). Simple effects indicated that CRH levels only at 31 weeks predicted preterm birth (F1,201 = 5.53, p = .02). Levels of cortisol were higher in women who delivered preterm at 15 weeks gestation (F1,201 = 4.45, p = .03) with a similar trend at 19 weeks gestation. Hierarchical regression suggested that the influence on birth outcome of maternal cortisol early in pregnancy was mediated by its influence on placental CRH at 31 weeks. Elevated cortisol at 15 weeks predicted the surge in placental CRH at 31 weeks (R = .49, d.f. = 1,199, Fchange = 61.78, p < .0001). Every unit of change in cortisol (microg/dl) at 15 weeks was associated with a 34 unit change of CRH (pg/ml) at 31 weeks. These findings suggested that early detection of stress signals by the placenta stimulated the subsequent release of CRH and resulted in increased risk for preterm delivery.

Maternal prenatal anxiety and corticotropin-releasing hormone associated with timing of delivery

Objective: The high rate of preterm births is an imposing public health issue in the United States. Past research has suggested that prenatal stress, anxiety, and elevated levels of maternal plasma corticotropin-releasing hormone (CRH) are associated with preterm delivery in humans and animals. Studies to date have not examined all three variables together; that is the objective of this paper. Methods: Data from 282 pregnant women were analyzed to investigate the effect of maternal prenatal anxiety and CRH on the length of gestation. It was hypothesized that at both 18 to 20 weeks (Time 1) and 28 to 30 weeks gestation (Time 2), CRH and maternal prenatal anxiety would be negatively associated with gestational age at delivery. CRH was also expected to mediate the relationship between maternal prenatal anxiety and gestational age at delivery. Results: Findings supported the mediation hypothesis at Time 2, indicating that women with high CRH levels and high maternal prenatal anxiety at 28 to 30 weeks gestation delivered earlier than women with lower CRH levels and maternal prenatal anxiety. Women who delivered preterm had significantly higher rates of CRH at both 18 to 20 weeks gestation and 28 to 30 weeks gestation (p < .001) compared with women who delivered term. Conclusions: These findings are the first to link both psychosocial and neuroendocrine factors to birth outcomes in a prospective design. ANOVA = analysis of variance; BIPS = Behavior in Pregnancy Study; CRH = corticotropin-releasing hormone; HPA = hypothalamic-pituitary-adrenal axis; SNS = sympathetic nervous system.

Familialism, social support, and stress: positive implications for pregnant Latinas.

This study examined the association of familialism, a cultural value that emphasizes close family relationships, with social support, stress, pregnancy anxiety, and infant birth weight. Foreign-born Latina (n = 31), U.S.-born Latina (n = 68), and European American (n = 166) women living in the United States participated in a prospective study of pregnancy in which they completed measures of familialism, social support, stress, and pregnancy anxiety during their second trimester. As expected, Latinas scored higher on familialism than European Americans. Familialism was positively correlated with social support and negatively correlated with stress and pregnancy anxiety in the overall sample. As predicted, however, the associations of familialism with social support and stress were significantly stronger among Latinas than European Americans. Moreover, higher social support was associated with higher infant birth weight among foreign-born Latinas only. Implications of cultural values for relationships and health are discussed.

Close relationship processes and health: implications of attachment theory for health and disease.

OBJECTIVES Health psychology has contributed significantly to understanding the link between psychological factors and health and well-being, but it has not often incorporated advances in relationship science into hypothesis generation and study design. We present one example of a theoretical model, following from a major relationship theory (attachment theory) that integrates relationship constructs and processes with biopsychosocial processes and health outcomes. METHOD We briefly describe attachment theory and present a general framework linking it to dyadic relationship processes (relationship behaviors, mediators, and outcomes) and health processes (physiology, affective states, health behavior, and health outcomes). We discuss the utility of the model for research in several health domains (e.g., self-regulation of health behavior, pain, chronic disease) and its implications for interventions and future research. RESULTS This framework revealed important gaps in knowledge about relationships and health. Future work in this area will benefit from taking into account individual differences in attachment, adopting a more explicit dyadic approach, examining more integrated models that test for mediating processes, and incorporating a broader range of relationship constructs that have implications for health. CONCLUSIONS A theoretical framework for studying health that is based in relationship science can accelerate progress by generating new research directions designed to pinpoint the mechanisms through which close relationships promote or undermine health. Furthermore, this knowledge can be applied to develop more effective interventions to help individuals and their relationship partners with health-related challenges.

Pregnancy affects appraisal of negative life events.

OBJECTIVE It has been demonstrated that physiological responses to stress are diminished late in pregnancy. This study investigates whether emotional responding is diminished as well by measuring affective responses to specific life events during pregnancy. METHODS A total of 292 pregnant women reported the occurrence of and affective responses to a range of major life events during gestation. Two analyses were conducted (across events and within events) on these responses to determine whether life events occurring in the first trimester were rated as more stressful than those that occurred in the third trimester. RESULTS Both within-event and across-events analyses of responses to life events demonstrated that events occurring early in pregnancy were perceived as more stressful than events occurring later in pregnancy. CONCLUSION Responses to stress and affective state are progressively altered in pregnant women, suggesting that timing of stress exposure during gestation may be critical in determining its impact.

MODELING THE TYPES AND TIMING OF STRESS IN PREGNANCY

In the current study we examined whether or not stress at critical intervals during pregnancy, or stress consistently experienced across the course of pregnancy was associated with gestational age in a (large) multiethnic sample. After deriving a latent trait-state model of stress, we examined whether or not particular components of stress (i.e., perceived stress, general anxiety, pregnancy-specific anxiety), or stress in general, at specific time points or over time were associated with gestational age. Pregnancy-specific anxiety over the course of pregnancy was associated with shorter gestation after controlling for a number of risk factors, including history of diabetes, smoking, maternal age, and parity. Moreover, these findings suggest that the relation between pregnancy-specific anxiety and gestational age was similar across ethnic groups. The importance of modeling the components and timing of stress with latent variable methodology is discussed.

Poor Sleep Quality is Associated with Preterm Birth

STUDY OBJECTIVES Preterm birth (PTB) is a major public health priority and the most common adverse pregnancy outcome. Several risk factors have been identified, but a gap in the understanding of the underlying etiology of PTB persists. Poor sleep quality is a correlate of adverse health outcomes. Therefore, we evaluated whether sleep quality during pregnancy was a clinically relevant risk factor for PTB. DESIGN Observational. MEASUREMENTS AND RESULTS Participants included 166 pregnant women (mean age = 28.6 ± 5.5 years). Self-report questionnaires, including the Pittsburgh Sleep Quality Index (PSQI), were administered at 14-16, 24-26, and 30-32 weeks gestation. Logistic regression models were used to evaluate whether sleep quality was associated with preterm delivery. Poor sleep quality was a predictor of preterm birth, with the largest effects in early pregnancy (14-16 weeks) (OR: 1.25 95% CI [1.04-1.50], P = 0.02) and more modest effects in later pregnancy (30-32 weeks) (OR: 1.18 95% CI [0.98-1.42], P = 0.07). With every one-point increase on the PSQI, the odds of preterm birth increase 25% in early pregnancy and 18% in later pregnancy. CONCLUSIONS Poor sleep quality, in both early and late pregnancy, is associated with an increased risk of delivering preterm. Currently the specific pathway(s) through which disturbed sleep contributes to PTB are unknown. We suggest that poor sleep may contribute to increased risk for PTB both independently, as well as in conjunction with other established risk factors, such as stress.

Corticotropin-Releasing Hormone during Pregnancy Is Associated with Infant Temperament

During pregnancy corticotropin-releasing hormone (CRH) is released into maternal and fetal circulation from the placenta. Elevated concentrations of placental CRH are associated with spontaneous preterm birth, but the consequences for infant development, independent of birth outcome, are unknown. In this study, the effects of placental CRH on infant temperament were examined in a sample of 248 full-term infants. Maternal blood samples were collected at 19, 25 and 31 weeks of gestation for CRH analysis. Infant temperament was assessed with measures of fear and distress at 2 months of age. Infants of mothers with low CRH at 25 weeks of gestation scored lower in fear and distress at 2 months. CRH at 19 and 31 weeks’ gestation was not significantly associated with measures of infant temperament, suggesting the possibility that there is a sensitive period for its effects. These data suggest that prenatal exposure to CRH may exert influences that persist into the postnatal period.