Quantitative meta-analysis of maternal prenatal salivary cortisol and newborn birthweight does not identify effect of fetal sex

Maternal early life and prenatal stress in relation to birth outcomes in Argentinian mothers

Environmental influences before and during pregnancy significantly impact offspring development. This study investigates open research questions regarding the associations between maternal early life stress (ELS), prenatal psychosocial stress, prenatal hair cortisol (HC), and birth outcomes in Argentinian women. Data on ELS, prenatal life events, HC (two samples representing first and second half of pregnancy), and birth outcomes were collected from middle-class Argentinian women (N = 69) upon delivery. Linear mixed models indicated that HC increased from the first half to the second half of pregnancy with considerable variability in the starting values and slopes between individuals. Mothers who experienced more ELS, were taller, or more educated, tended to show lower increases in HC. Older age was positively related to HC increases. Our data did not suggest an interaction between ELS and prenatal life events in relation to HC. We found that the change in HC was most likely negatively associated with birth weight. Our data are most compatible with either a weak or the absence of an association between ELS or prenatal life events and absolute values of HC. Mothers with stronger increases in hair cortisol tended to have newborns with slightly lower birth weight. Hence, ELS and birthweight may either have been related to changes in cortisol exposure during pregnancy or to factors that influence accumulation or retention of cortisol in hair.

Maternal serum cortisol levels during pregnancy differ by fetal sex

BACKGROUND

Males and females have different patterns of fetal growth, resulting in different sizes at birth. Increased maternal cortisol levels in pregnancy negatively impact fetal growth. However, it is unknown whether sexual dimorphism displays differences in maternal cortisol levels already during early pregnancy and to what extent it explains sex differences in intra-uterine growth. The present cross-sectional study investigated whether fetal sex was associated with the level of maternal serum total cortisol in first half of pregnancy and its contribution to sex differences in fetal growth.

METHOD

The study population comprised 3049 pregnant women from the Amsterdam Born Children and their Development (ABCD)-cohort). Total serum cortisol levels were determined during pregnancy. Multivariable linear regression was used to determine fetal sex differences in maternal cortisol levels and its association with sex differences in fetal growth measured as birth weight standardized for gestational age, parity and sex.

RESULTS

Maternal serum total cortisol increased during pregnancy from on average 390 ± 22 nmol/L (at 5th week) to 589 ± 15 nmol/L (at 20th week). Women carrying a female fetus had higher maternal total cortisol levels. This sex difference was not significant before the 11th week; at the 12th week the difference was 15 ± 7 nmol/L which increased to 45 ± 22 nmol/L at the 20th week (p-for-interaction=0.05). Maternal total cortisol levels were associated with birth weight (ß:-0.22;P < 0.001). However, sex differences in birth weight were not explained by related maternal total cortisol levels.

CONCLUSION

The sexual dimorphic maternal serum total cortisol levels are apparent after the first trimester but do not explain the different patterns of fetal growth.

The role of cortisol in the association between prenatal air pollution and fetal growth: A prospective cohort study

Prenatal air pollutant exposure has been linked to impaired fetal growth. However, its special vulnerability windows and biological mechanisms remain unclear. A prospective birth cohort study including 7419 mother-newborn pairs was conducted from 2015 to 2020 to determine critical exposure windows and examine whether cortisol mediates the relationship between air pollutant exposure and fetal growth. Air pollutant data for PM_2.5, PM₁₀, SO₂, and CO were obtained from the Hefei City Ecology and Environment Bureau. Data on fetal ultrasound measurements and birth size were collected. Maternal and cord blood samples were used for measuring cortisol. Prenatal air pollutant (PM_2.5, PM₁₀, SO₂, and CO) exposure, particularly in the first trimester, was associated with reduced fetal size from later pregnancy to birth. An IQR increase in PM_2.5 (β = 0.082, 95%CI: 0.029, 0.135), PM₁₀ (β = 0.086, 95%CI: 0.036, 0.136), SO₂ (β = 0.086, 95%CI: 0.028, 0.144), and CO (β = 0.063, 95%CI: 0.017, 0.109) exposure in the first trimester was associated with higher cord blood cortisol levels. Significant relationships were observed between air pollutant exposure in the first trimester and increased ratio of cord to maternal blood cortisol levels. Exposure to high levels of cord blood cortisol significantly reduced the Z scores of birth weight (β = -0.17, 95%CI: -0.23, -0.10), length (β = -0.09, 95%CI: -0.16, -0.03), and head circumference (β = -0.33, 95%CI: -0.42, -0.25). Mediation analysis showed that the association of air pollutant exposure in the first trimester with neonatal parameters mediated by cord blood cortisol was 20.62%. These results indicated that air pollutant exposure during pregnancy could reduce fetal growth by the increased fetal cortisol levels due to placental barrier impairment, with the critical window of exposure occurring in the first trimester.

Anxiety and depressive symptoms in pregnancy predict low birth weight differentially in male and female infants-findings from an urban pregnancy cohort in India

PURPOSE

This study examined the contributions of antenatal anxiety, depression, and partner violence to low birth weight (LBW) in infants and to sex-specific birth weight outcomes among mothers from a cohort in urban India.

METHODS

Data from 700 mothers from the PRAMMS cohort (Prospective Assessment of Maternal Mental Health Study) were used. Pregnant women were assessed in each trimester-T1, T2 and T3, for symptoms of anxiety, and depression as well as partner violence. Multivariate analyses were performed for the whole sample and then for male and female infants separately. The final multivariable logistic regression models were each built using a backward selection procedure and controlling for confounders. To accommodate longitudinally measured data, change in scores (T2-T1 and T3-T2) of anxiety and depression were included in the model.

RESULTS

Of the 583 women with a singleton live birth, birth weight was available for 514 infants  and LBW was recorded in 80 infants (15.6%). Of these, 23 infants were preterm. Overall, higher T1 Depression scores (OR: 1.11; 95% CI 1.040, 1.187) and an increase in both Depression scores (OR: 1.12; 95% CI 1.047, 1.195) from T1 to T2 and Anxiety scores (OR: 1.32; 95% CI 1.079, 1.603) between T2 and T3 were predictors of LBW. Female infants had a higher chance of LBW with increase in maternal anxiety between T1-T2 (OR: 1.69; 95% CI 1.053, 2.708) and T2-T3 (OR: 1.49; 95% CI 1.058, 2.086); partner violence during pregnancy just failed to reach conventional statistical significance (OR: 2.48; 95% CI 0.810, 7.581) in girls. Male infants had a higher chance of LBW with higher baseline depression scores at T1 (OR: 1.23; 95% CI 1.042, 1.452) and an increase in depression scores (OR: 1.25; 95% CI 1.060, 1.472) from T1 to T2.

CONCLUSION

Increasing prenatal anxiety and depressive symptoms in different trimesters of pregnancy were associated with LBW with sex-specific patterns of association in this sample from a Low and Middle Income Country.

Prenatal greenspace exposure and cord blood cortisol levels: A cross-sectional study in a middle-income country

Exposure to greenspace has been associated with reduced stress; however, the available evidence on such an association for the fetus is still very scarce. We, for the first time, investigated the association between maternal greenspace exposure and the level of cortisol, a stress hormone, in the cord blood. Our study was based on a cohort of 150 pregnant women in Sabzevar, Iran (2018). We comprehensively assessed greenspace exposure for each participant through (i) residential surrounding greenspace (using two satellite-derived vegetation indices), (ii) residential proximity to green spaces, (iii) maternal visual access to greenspace, (iv) use of public and private green spaces, (v) having a private garden, and (vi) the number of plant pots at home. Linear regression models were developed to assess the association of each indicator of greenspace exposure with cord blood cortisol levels, controlled for the relevant covariates. We observed that a higher residential surrounding greenspace (100 m buffer), having a window with greenspace view, window greenspace coverage of more than 50%, frequently looking at greenspace through window, residential proximity to large green spaces, and more time spent in green spaces were associated with lower cortisol levels in the cord blood. The findings for residential surrounding greenspace at 300 m and 500 m buffers, residential proximity to any green space regardless of its size, having a private garden, and number of plant pots at home were not conclusive. While about one-third of the association between residential surrounding greenspace (100 m buffer) could be mediated through reduction in exposure to air pollution, we did not observe any strong evidence for such a mediatory role for the visual access to greenspace. The findings stratified for parental education and housing type showed mixed patterns. Our findings suggest that more greenspace exposure might reduce cortisol level in the cord blood.

Maternal exposure to air pollution during pregnancy and cortisol level in cord blood

Exposure to air pollution has been associated with disorders of the endocrine system and hypothalamic-pituitary-adrenal (HPA) axis; however, the available evidence on these associations is still scarce. This study aimed to investigate, for the first time, the association of exposure to PM₁, PM_2.5, and PM₁₀, as well as traffic indicators (distance to major roads and total street length in different buffers around maternal residential address) during pregnancy with cortisol level in cord blood samples. This cross-sectional study was carried out based on 150 mother-newborn pairs in Sabzevar, Iran (2018). Land use regression models were applied to estimate air pollution exposure during the entire pregnancy at maternal residential addresses. Multiple linear regression models were applied to estimate the association of exposure to air pollution during pregnancy and cord blood cortisol levels, controlled for relevant covariates. There was a significant positive association between exposure to PM_2.5 and PM₁₀ and cortisol levels in cord blood (β = 2.55, 95% confidence intervals (CI) = 0.57, 4.52, P-value = 0.01, and β = 3.09, 95% CI: 1.28, 4.90, P-value < 0.01, respectively). Moreover, there was a significant positive association between total street length in a 100 m buffer around maternal residence and cortisol level. Each one interquartile range (IQR) increase in distance from home to major roads was associated with a -2.58 (95% CI: -4.85, -0.30, P-value = 0.03) decrease in cord blood cortisol level. The median (IQR) of the cord blood cortisol levels for the first and fourth quartiles of distance to major roads were 50.7 (19.5) and 38.2 (20.4) ng/mL, respectively. The associations for total street length in 300 m and 500 m buffers and PM₁ exposure were not statistically significant. Our findings suggest a direct association of exposure to air pollution during pregnancy and cortisol levels at cord blood.