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Open Access Publications from the University of California

Scholarly Works (25 results)

  • Article
  • Peer Reviewed
UC Irvine Previously Published Works (2007)
Significant ethnic disparities exist in reproductive outcomes. A potential contributing factor may be the functioning of the hypothalamic-pituitary-adrenal (HPA) axis and placenta during pregnancy. In the present study, levels of cortisol, ACTH and CRH were determined longitudinally from the plasma of 310 African American, Hispanic and non-Hispanic White women at 18-20, 24-26 and 30-32 weeks' gestation. During pregnancy, African American women exhibited lower levels of cortisol than non-Hispanic women and higher levels of ACTH than Hispanic women. The trajectory of CRH increase also differed by ethnicity, with African Americans exhibiting the lowest levels both early and late in pregnancy. Higher levels of cortisol at 18-20 weeks were associated with higher levels of CRH at 30-32 weeks among the African American and Hispanic women, but not among non-Hispanic women. Ethnic differences persisted when adjusting statistically for sociodemographic and biomedical factors. The findings are consistent with the possibility that ethnic disparities in adverse birth outcomes may be due, in part, to differences in HPA axis and placental function.
    Cover page: Ethnic differences in adrenocorticotropic hormone, cortisol and corticotropin-releasing hormone during pregnancyCreative Commons 'BY' version 4.0 license
    • Article
    • Peer Reviewed
    UC Irvine Previously Published Works (1995)
    In a prospective study, third trimester plasma levels of BE and ACTH were determined in 58 women who delivered vaginally. Peptide regulation was compared between subjects who used conduction anesthesia at delivery and subjects who did not. Third trimester levels of maternal BE and ACTH were significantly related; however, the relationship was significant only in subjects who did not receive conduction anesthesia (n = 24) at delivery. The normal co-release pattern between BE and ACTH in subjects receiving conduction anesthesia (n = 34) during birth was uncoupled. The use of conduction analgesia during vaginal delivery was significantly related to a disregulation index created to quantify the BE-ACTH release pattern. Uncoupled ACTH and BE patterns may result from modified control of pro-opiomelanocortin (POMC) expression during pregnancy or unique proteolytic processing of POMC, and may alter pain tolerance during delivery.
      Cover page: Third trimester POMC disregulation predicts use of anesthesia at vaginal deliveryCreative Commons 'BY' version 4.0 license
      • Article
      • Peer Reviewed
      UC Irvine Previously Published Works (2003)
      Maternal peptides from the hypothalamic-pituitary-adrenal (HPA) axis rise during human pregnancy. The effects of circulating maternal adrenocorticotropin (ACTH) and beta-endorphin (BE) on human fetal behavior was determined in 135 women during their 32nd week of gestation. Fetal behavior was measured by assessing heart rate habituation to a series of repeated vibroacoustic stimuli. Individual differences in habituation were determined by computing the number of consecutive responses above the standard deviation during a control period. There was no significant relation between levels of ACTH, BE and the rate of fetal heart rate habituation. However, an index of HPA disregulation (uncoupling of ACTH and BE) was related significantly to fetal behavior. Fetal exposure to high levels of maternal BE relative to ACTH was associated with significantly lower rates of habituation. Results indicate that maternal stress and stress-related peptides influence fetal response patterns. It is possible that this influence persists over the life span.
        Cover page: Maternal Hypothalamic-Pituitary-Adrenal Disregulation during the Third Trimester Influences Human Fetal ResponsesCreative Commons 'BY' version 4.0 license
        • Article
        • Peer Reviewed
        UC Irvine Previously Published Works (2008)
        Self-injuring behavior (SIB) is a life-threatening behavior exhibited by many species, including humans, and has no known cause and no agreed upon treatment. The role of the stress axis in the maintenance of this mysterious behavior was examined in subjects with life-long SIB. Over a 6-year period, 40 hr of direct observations of behavior and the environment were recorded on palmtop computers while 36 residential subjects (28 target and 8 control subjects) conducted their daily activities. Blood samples were collected in morning and evening for all subjects and within minutes after a self-injuring act in 28 target subjects who exhibited SIB to determine levels of ACTH and B-endorphin (BE). Self-injuring events in the patient group were significantly sequentially dependent (i.e., the only predictor of a self-injuring act was an antecedent self-injuring act). Higher morning levels of BE relative to ACTH predicted [r(df=27) = .57, p < .001] the sequentially dependent pattern of SIB. This effect was validated in a subgroup retested several months later [r(df=22) = .60, p < .001]. A subgroup of seven subjects exhibiting sequentially dependent patterns were administered an opiate blocker (naltrexone) in a double-blind, crossover design with an additional 14 hr/week of observation for 7 weeks. Naltrexone challenge interrupted the sequential pattern (improved behavior) in subjects with elevated BE immediately following SIB (r = .85, p < .01). The pattern of results supported the conclusion that the stress axis played a significant role in the maintenance of complex episodes of self-injury.
          Cover page: The role of proopiomelanocortin (POMC) in sequentially dependent self‐injurious behaviorCreative Commons 'BY' version 4.0 license
          • Article
          • Peer Reviewed
          UC Irvine Previously Published Works (2006)
          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.
            Cover page: Elevated maternal cortisol early in pregnancy predicts third trimester levels of placental corticotropin releasing hormone (CRH): Priming the placental clockCreative Commons 'BY' version 4.0 license
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2007)

            OBJECTIVE: This study examined women's mood responsiveness associated with patterns of stress hormone levels in everyday situations. METHODS: Self-reports of negative, positive, and energy dimensions of mood were obtained from 203 nurses throughout the day on a workday and on an off-work day during the luteal and follicular phases of the menstrual cycle. Individual differences in daytime norepinephrine and cortisol were assessed. RESULTS: Patterns of norepinephrine and cortisol levels were associated with ratings of the following moods: tired, sad, and happy. Phase of the menstrual cycle and the day factor (workday, off-work day) modified the association of mood ratings and stress hormone patterns. CONCLUSION: The experience of negative mood is associated with both hypoarousal and hyperarousal conditions. A homeostatic arousal-related concept of mood regulation is discussed.

              Cover page: Moods in everyday situations: effects of combinations of different arousal-related factors.
              • Article
              • Peer Reviewed
              UC Irvine Previously Published Works (2008)
              Elevation in placental corticotropin-releasing hormone (pCRH) during the last trimester of pregnancy has been associated with an increased risk for preterm delivery. Less is known about the consequences for the human fetus exposed to high levels of pCRH early in pregnancy. pCRH levels were measured in 138 pregnant women at least once at 15, 20 and 25 weeks of gestation. At 25 weeks of gestation, fetal heart rate (FHR) responses to a startling vibroacoustic stimulus (VAS) were recorded as an index of maturity. pCRH levels at 15 weeks of gestation, but at no later point, predicted FHR responses to the VAS. Fetuses exposed to the lowest concentrations of pCRH at 15 weeks of gestation exhibited a distinguishable response to the VAS, whereas fetuses exposed to higher levels of pCRH did not respond. The findings suggest that exposure to low levels of pCRH early in gestation may be optimal and associated with a response pattern indicating greater maturity.
                Cover page: Low Levels of Corticotropin-Releasing Hormone during Early Pregnancy Are Associated with Precocious Maturation of the Human FetusCreative Commons 'BY' version 4.0 license
                • Article
                • Peer Reviewed
                UC Irvine Previously Published Works (2001)

                Objective

                The purpose of the study was to assess the effects of the timing of stress during pregnancy on emotional responses and birth outcome. We hypothesized that as pregnancy advanced women would become increasingly resistant to the adverse effects of stress, and so early stress would have more profound effects than later stress.

                Study design

                Forty pregnant women who had experienced an earthquake during pregnancy or shortly afterward were identified. Using regression analyses we determined whether the timing of the earthquake was related to an affective response to this event and to length of gestation.

                Results

                The earthquake was rated as more stressful when it occurred early in pregnancy compared with late in pregnancy, and postpartum ratings were similar to first-trimester ratings (r (quad) =.39; P <.05). Stress experienced early in pregnancy was associated with shorter gestational length (r =.35; P <.05).

                Conclusions

                As pregnancy advances, women become decreasingly sensitive to the effects of stress. This decrease in vulnerability may reflect increasing protection of the mother and fetus from adverse influences during pregnancy.
                  Cover page: When stress happens matters: Effects of earthquake timing on stress responsivity in pregnancyCreative Commons 'BY' version 4.0 license
                  • Article
                  • Peer Reviewed
                  UC Irvine Previously Published Works (2007)

                  Background

                  Accumulating evidence indicates that prenatal maternal and fetal processes can have a lasting influence on infant and child development. Results from animal models indicate that prenatal exposure to maternal stress and stress hormones has lasting consequences for development of the offspring. Few prospective studies of human pregnancy have examined the consequences of prenatal exposure to stress and stress hormones.

                  Method

                  In this study the effects of prenatal maternal psychosocial (anxiety, depression, and perceived stress) and endocrine (cortisol) indicators of stress on infant temperament were examined in a sample of 247 full-term infants. Maternal salivary cortisol and psychological state were evaluated at 18-20, 24-26, and 30-32 weeks of gestation and at 2 months postpartum. Infant temperament was assessed with a measure of negative reactivity (the fear subscale of the Infant Temperament Questionnaire) at 2 months of age.

                  Results

                  Elevated maternal cortisol at 30-32 weeks of gestation, but not earlier in pregnancy, was significantly associated with greater maternal report of infant negative reactivity. Prenatal maternal anxiety and depression additionally predicted infant temperament. The associations between maternal cortisol and maternal depression remained after controlling for postnatal maternal psychological state.

                  Conclusions

                  These data suggest that prenatal exposure to maternal stress has consequences for the development of infant temperament.
                    Cover page: Prenatal Exposure to Maternal Depression and Cortisol Influences Infant TemperamentCreative Commons 'BY' version 4.0 license
                    • Article
                    • Peer Reviewed
                    UC Irvine Previously Published Works (2005)

                    Objective: This study examined women’s mood responsiveness on work and off days during different phases of the menstrual cycle. Methods: Self reports of negative, positive, and energy dimensions of mood were obtained throughout the day on two work and two off days during the luteal and follicular phases of the menstrual cycle in 203 women nurses. Individual differences in daytime and nighttime epinephrine, norepinephrine, and cortisol were assessed. Results: High daytime norepinephrine, epinephrine, and cortisol levels were associated with higher ratings of stress and tired, and with lower ratings of happy. Phase of the menstrual cycle and the day factor (work day, off day) were also associated with mood differences, and the direction of the effects depended on hormone levels and hormone sampling period. Conclusion: The experience of moods is affected by arousal-related interaction of hormone levels with phase of the menstrual cycle and occupational stress.

                      Cover page: Moods in everyday situations: Effects of menstrual cycle, work, and stress hormones
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