Relationships Among Number of Stressors, Perceived Stress, and Salivary Cortisol Levels During the Third Trimester of Pregnancy

OBJECTIVE

To examine relationships among the number of stressors, perceived stress, and salivary cortisol levels during the third trimester of pregnancy.

DESIGN

Secondary analysis of cross-sectional data.

SETTING

Participants' homes.

PARTICIPANTS

Women during the third trimester of pregnancy (N = 73).

METHODS

Participants provided saliva samples at four time points over 2 days for cortisol assay and completed questionnaires to assess stressors and perceived stress. We computed multiple linear regression models to examine the relationships among the number of stressors and perceived stress to cortisol awakening response, diurnal slope, and overall cortisol secretion. We also computed a multiple linear regression model to examine the relationship between perceived stress and the number of stressors.

RESULTS

Greater perceived stress was associated with reduced overall cortisol secretion across the day (β = -0.41, p = .01). The number of stressors was associated with perceived stress (β = 0.48, p = .002) but not salivary cortisol measures.

CONCLUSION

Elevated perceived stress and the related cortisol alterations that we identified could represent salient targets for enhancing hypothalamic-pituitary-adrenal axis function during the third trimester. Perceived stress may shape the relationship between exposure to stressors and cortisol response during pregnancy. Future research is warranted to confirm study results and to understand the implications for parturition and fetal development.

Exposure to prenatal stressors and infant autonomic nervous system regulation of stress

OBJECTIVES

The purpose of this study was to determine the relationship between fetal exposure to maternal prenatal stressors and infant parasympathetic (PNS) and sympathetic (SNS) nervous function at 3 timepoints across the first year of life.

BACKGROUND

Autonomic nervous system impairments may mediate associations between gestational exposure to stressors and later infant health problems. Heart rate variability (HRV) provides a sensitive index of PNS and SNS function. However, no studies have assessed longitudinal associations between prenatal stressors and infant HRV measures of both PNS and SNS over the first year of life.

METHODS

During the third trimester of pregnancy, 233 women completed measures of life stressors and depression. At 1, 6 and 12 months of age, a stressor protocol was administered while infant electrocardiographic (ECG) data were collected from a baseline through a post-stressor period. HRV measures of PNS and SNS activity (HF, LF, LF/HF ratio) were generated from ECG data. We used multilevel regression to examine the aims, adjusting for maternal depression and neonatal morbidity.

RESULTS

There were no associations between prenatal stressors and any baseline or reactivity HRV metric over the infant's first year of life. However, exposure to more stressors was associated with lower post-stressor LF HRV at both 6 (β = -.44, p = .001) and 12 (β = -.37, p = .005) months of age.

CONCLUSIONS

Findings suggest potential alterations in development of the vagally mediated baroreflex function as a result of exposure to prenatal stressors, with implications for the infants' ability to generate a resilient recovery in response to stressors.

The effect of time interval between antenatal corticosteroid administration and delivery on outcomes in late preterm neonates born to mothers with diabetes: a retrospective cohort study

Objectives

The study aims to investigate whether the time interval between administering antenatal corticosteroids (ACS) and delivery influences the neonatal outcomes in late preterm (LPT) neonates (34 + 0 to 36 + 6 weeks) born to mothers with diabetes.

Study design

This retrospective cohort study included women with any type of diabetes who gave birth between 34 + 0 weeks and 36 + 6 weeks of gestation. Based on the time interval between the first dose of corticosteroid and delivery, the cases were stratified into the following groups: <2, 2-7, and >7 days. Women unexposed to ACS served as the control group. The primary outcomes included the incidence of neonatal hypoglycemia and respiratory distress syndrome/transient tachypnea of the newborn. Multivariate logistic regression was used to assess the relationship between the time interval and neonatal outcomes and adjust for potential confounders.

Results

The study enrolled a total of 636 parturients. Among them, 247 (38.8%) delivered within 2 days after ACS administration, 169 (26.6%) within 2-7 days, and 126 (19.8%) at >7 days. Baseline characteristics such as type of diabetes, methods of glycemic control, preterm premature rupture of membrane, placenta previa, cesarean delivery, indication for delivery, percentage of large for gestational age, birth weight, and HbA1c in the second or third trimester were significantly different among the four groups. The multivariate analysis showed no statistically significant difference in the incidence of primary or secondary neonatal outcomes between the case and control groups.

Conclusions

ACS treatment was not associated with neonatal hypoglycemia and respiratory outcomes in LPT neonates born to diabetic mothers, regardless of the time interval to delivery.

Exposure to antenatal corticosteroids and infant cortisol regulation

Administration of antenatal corticosteroids (AC) is the standard of care during pregnancy for women who are at risk of early delivery. Evidence indicates that AC improve survival and reduce morbidity for preterm infants. However, research suggests that infants whose mothers receive AC have an altered hypothalamic-pituitary-axis (HPA) response to stressors in early life. Results are mixed regarding the nature of these effects, with studies showing both suppressed and augmented HPA activity. In addition, research is very limited beyond the 4th month of life. The purpose of this study was to determine if AC exposure was associated with infant cortisol levels in a resting state or in response to a stressor at 1, 6 and 12 months postnatal. We also evaluated the moderating role of preterm birth in this association. 181 women and their infants participated in the study. Women were recruited during the 3rd trimester of pregnancy; at this time, they completed the Perceived Stress Scale and provided 8 salivary samples over a 2-day period for cortisol assay. They provided these data again at 6 and 12 months postnatal. At 1, 6, and 12 months postnatal, salivary samples were collected from infants to examine their cortisol levels before and after participation in a 'stressor protocol'. Data were extracted from the medical record on AC exposure, gestational age, maternal obstetric risk, and neonatal morbidity. Mixed effects multilevel regression modeling was used to examine the aims. Infants whose mothers received AC had significantly lower resting state (B = -2.47, CI: -3.691, -0.0484) and post-stressor (B = -2.51, CI: -4.283, -0.4276) cortisol levels across the first year of life than infants whose mothers did not receive AC. There was no moderating effect of preterm birth on the relationship between AC exposure and cortisol. Results indicate a state of dampened HPA activation and cortisol hypo-arousal that persists across the first year of life among infants who were exposed to corticosteroids in utero. Further research is needed to examine mechanisms responsible for any alterations that occur during development of the fetal HPA axis, including epigenetic and biochemical factors that control hormonal secretion, negative feedback, and glucocorticoid receptor function throughout the HPA axis. Findings warrant careful consideration by obstetric clinicians of the benefits and risks of prescribing AC.

Clinical determinants of cerebrovascular reactivity in very preterm infants during the transitional period

BACKGROUND

Preterm infants are at enhanced risk of brain injury due to altered cerebral haemodynamics during postnatal transition. This observational study aimed to assess the clinical determinants of transitional cerebrovascular reactivity and its association with intraventricular haemorrhage (IVH).

METHODS

Preterm infants <32 weeks underwent continuous monitoring of cerebral oxygenation and heart rate over the first 72 h after birth. Serial cranial and cardiac ultrasound assessments were performed to evaluate the ductal status and to diagnose IVH onset. The moving correlation coefficient between cerebral oxygenation and heart rate (TOHRx) was calculated. Linear mixed-effect models were used to analyse the impact of relevant clinical variables on TOHRx. The association between TOHRx and IVH development was also assessed.

RESULTS

Seventy-seven infants were included. A haemodynamically significant patent ductus arteriosus (hsPDA) (β = 0.044, 95% CI: 0.007-0.081) and ongoing dopamine treatment (β = 0.096, 95% CI: 0.032-0.159) were associated with increasing TOHRx, indicating impaired cerebrovascular reactivity. A significant association between TOHRx, mean arterial blood pressure (β = -0.004, 95% CI: -0.007, -0.001) and CRIB-II score (β = 0.007, 95% CI: 0.001-0.015) was also observed. TOHRx was significantly higher in infants developing high-grade IVH compared to those without IVH.

CONCLUSIONS

Dopamine treatment, low blood pressure, hsPDA and high CRIB-II are associated with impaired cerebrovascular reactivity during postnatal transition, with potential implications on IVH development.

IMPACT

The correlation coefficient between cerebral oxygenation and heart rate (TOHRx) provides a non-invasive estimation of cerebrovascular reactivity, whose failure has a potential pathogenic role in the development of IVH in preterm infants. This study shows that cerebrovascular reactivity during the transitional period improves over time and is affected by specific clinical and therapeutic factors, whose knowledge could support the development of individualized neuroprotective strategies in at-risk preterm infants. The evidence of increased TOHRx in infants developing high-grade compared to low-grade or no IVH during the transitional period further supports the role of impaired cerebrovascular reactivity in IVH pathophysiology.

Respiratory and glycemic control outcomes of late preterm infants after antenatal corticosteroid exposure

OBJECTIVE

To quantify changes in respiratory and glycemic control outcomes following antenatal corticosteroids (ANCS) exposure in late preterm neonates.

DESIGN/METHODS

The study included 500 neonates born between 34 0/7 and 36 6/7 weeks of gestation. Study population was divided into two groups: an immature group (34 0/7-35 6/7 weeks) and a mature group (36 0/7-36 6/7 weeks). Respiratory and glycemic control outcomes were analyzed for each group independently.

RESULTS

In the immature group, the odds of developing respiratory distress decreased in neonates exposed to ANCS within 7 days of delivery (aOR 0.42; p = 0.02). In the mature group, ANCS exposure did not change respiratory outcomes, but decreased lowest blood glucose levels (-1.5 ± 0.66 mg/dL per dose, p = 0.02).

CONCLUSION

In our study cohort, ANCS administration was associated with improved neonatal respiratory outcomes only for infants in the immature 34 0/7-35 6/7 weeks of gestational age group. ANCS was associated with altered glycemic control only in infants in the mature 36 0/7-36 6/7 weeks of gestational age group.

Prematurity alters skin conductance and behavioural scoring after acute stress in term-equivalent age infants

AIM

The primary objective was to assess the effect of prematurity at term-equivalent age on skin conductance and behavioural responses to acute stress. The secondary objective was to explore the reliability of skin conductance in detecting neonatal discomfort in preterm and full-term populations.

METHODS

Very preterm infants at term-equivalent age and healthy full-term neonates, 34 infants in each group, underwent the hip dysplasia screening test. The acute pain in newborn infants (APN) scale was scored before and 15, 45 and 90 seconds after stimulus. Skin conductance was measured in the 30-second time-lap before and after stimulus.

RESULTS

The APN score was lower in preterm infants after intervention (term: 5.4 ± 2.8 vs. preterm: 3.9 ± 2.2; p = 0.03). Peaks-per-second, a skin conductance parameter, exhibited lower basal values in preterm infants than in term infants, with similar rise induced by stressful challenge. Peaks-per-second values were correlated to the 15-second APN score in both groups (term: r = 0.55, p < 0.001; preterm: r = 0.43, p = 0.01).

CONCLUSION

Preterm birth changed skin conductance signal and behavioural response to stress at term-equivalent age. The skin conductance device may be an objective tool for a continuous monitoring of acute neonatal stress.

Use of Glucocorticoids for the Fetus and Preterm Infant

The soon-to-be-delivered fetus and preterm infant have been treated with glucocorticoids to prepare for postnatal life, historically for more than 40 years. The use of glucocorticoids is as much for replacement of cortisol in the setting of a poorly functioning hypothalamic-pituitary-adrenal axis in the preterm infant, as it is for prevention of long-term lung dysfunction. Potential negative effects of glucocorticoid treatment on brain development and function have been observed more often with dexamethasone therapy than with use of other glucocorticoids. Overall, glucocorticoid treatment has improved the outcome of the preterm infant.

Associations Between Hormonal Biomarkers and Cognitive, Motor, and Language Developmental Status in Very Low Birth Weight Infants

BACKGROUND

Male infants are more prone to health problems and developmental delays than female infants.

OBJECTIVES

On the basis of theories of gender differences in brain development and social relationships, we explored associations between testosterone and cortisol levels with infant cognitive, motor, and language development ("infant development") in very low birth weight (VLBW) infants, controlling for mother-infant interactions, characteristics of mothers and infants, and days of saliva collection after birth.

METHODS

A total of 62 mother-VLBW infant pairs were recruited from the newborn intensive care unit of a tertiary medical center in the Southeast United States. Data were collected through infant medical record review, biochemical measurement, observation of mother-infant interactions, and standard questionnaires. Infant development was assessed at 6 months corrected age (CA), and mother-infant interactions were observed at 3 and 6 months CA.

RESULTS

General linear regression with separate analyses for each infant gender showed that high testosterone levels were positively associated with language development of male infants after controlling for mother-infant interactions and other covariates, whereas high cortisol levels were negatively associated with motor development of female infants after controlling for mother-infant interactions.

CONCLUSIONS

Steroid hormonal levels may well be more fundamental factors for assessing infant development than infant gender or mother-infant interactions at 6 months CA.

Associations of Maternal Testosterone and Cortisol Levels With Health Outcomes of Mothers and Their Very-Low-Birthweight Infants

OBJECTIVE

Although the roles of testosterone and cortisol in various health problems have been extensively investigated, little is known about their associations with health outcomes in mothers and their very-low-birthweight (VLBW) infants when maternal testosterone and cortisol are examined together during the postpartum period.

METHOD

The 101 mother-VLBW infant pairs were recruited from the neonatal intensive care unit of a tertiary medical center in the southeastern United States. Demographic information, pregnancy and labor complications of mothers, and health and growth outcomes of infants were obtained from medical records and interviews with mothers. Maternal salivary testosterone and cortisol levels were determined using enzyme immunoassay.

RESULTS

Linear regression showed that mothers who were older and had a larger body mass index experienced more pregnancy complications, whereas mothers who were single and had a cesarean section experienced more labor complications. Generalized linear models showed that mothers with high cortisol levels had more antepartum hemorrhage, whereas infants of mothers with high cortisol levels had fewer neurological insults and shorter hospitalizations than other infants. More mothers experienced premature prolonged rupture of membranes (PPROM) than chorioamnionitis, and maternal medical complications were negatively associated with infant health outcomes except PPROM, which was positively associated with infant outcomes.

CONCLUSIONS

High maternal cortisol levels were associated with maternal health problems during pregnancy. Beneficial effects of PPROM and high maternal cortisol levels on infant health outcomes were important findings, and understanding the mechanisms of these relationships may be of practical value for clinicians and researchers.

Preterm infants' behaviors and skin conductance responses to nurse handling in the NICU

Stress response patterns are indicative of the neonate's unique ability to cope with environmental demands and can be evaluated through autonomic and behavioral response parameters.

OBJECTIVE

To characterize stress responses during tactile stimulation to standard nurse handling in the NICU, and their association with severity of illness in preterm infants.

METHODS

Thirty preterm neonates were studied at postnatal day 4-5 during standard nurse caregiving. Heart rate (HR), respiratory rate (RR), skin conductance responses per second (SCR/s), and NIDCAP® stress behaviors were recorded before and during care. Non-parametric tests were used to assess differences from before to during care. Pearson's correlations were used to determine the association of biological and behavioral variables to the score for neonatal acute physiology (SNAP), a severity of illness index.

RESULTS

HR, RR, SCR/s and NIDCAP® behaviors (motor and attentional cues, and ability to self-console) increased from before to during the care (p < 0.01). NIDCAP® behaviors showed a significant negative association to the SNAP score (R = -0.45, p < 0.05).

CONCLUSIONS

HR, RR, SCR/s and NIDCAP® behaviors significantly increased during care. NIDCAP® stress behaviors were influenced by the severity of illness of the infant, while SCR/s was not influenced by severity of illness.