Effect of psychosocial stress and physical activity on preterm birth: a cohort study

Impact of maternal posture on fetal physiology in human pregnancy: a narrative review

In numerous medical conditions, including pregnancy, gravity and posture interact to impact physiology and pathophysiology. Recent investigations, for example, pertaining to maternal sleeping posture during the third trimester and possible impact on fetal growth and stillbirth risk highlight the importance and potential clinical implications of the subject. In this review, we provide an extensive discussion of the impact of maternal posture on fetal physiology from conception to the postpartum period in human pregnancy. We conducted a systematic literature search of the MEDLINE database and identified 242 studies from 1991 through 2021, inclusive, that met our inclusion criteria. Herein, we provide a synthesis of the resulting literature. In the first section of the review, we group the results by the impact of maternal posture at rest on the cervix, uterus, placenta, umbilical cord, amniotic fluid, and fetus. In the second section of the review, we address the impact on fetal-related outcomes of maternal posture during various maternal activities (e.g., sleep, work, exercise), medical procedures (e.g., fertility, imaging, surgery), and labor and birth. We present the published literature, highlight gaps and discrepancies, and suggest future research opportunities and clinical practice changes. In sum, we anticipate that this review will shed light on the impact of maternal posture on fetal physiology in a manner that lends utility to researchers and clinicians who are working to improve maternal, fetal, and child health.

Maternal Occupational Risk Factors and Preterm Birth: A Systematic Review and Meta-Analysis

Objective: This systematic review and meta-analysis aimed to summarize the evidence on the relationship between physical occupational risks (high physical workload, long working hours, shift work, whole-body vibrations, prolonged standing, and heavy lifting) and preterm birth. Methods: A systematic review and meta-analysis was conducted across six databases to investigate the relationship between physical occupational risks and preterm birth. Result: A comprehensive analysis of 37 studies with varying sample sizes found moderate evidence of positive associations between high physical workload, long working hours, shift work, whole-body vibration, and preterm birth. Meta-analysis showed a 44% higher risk (OR 1.44, 95% CI 1.25-1.66) for preterm birth with long working hours and a 63% higher risk (OR 1.63, 95% CI 1.03-2.58) with shift work. Conclusion: Pregnant women in physically demanding jobs, those working long hours or on shifts, and those exposed to whole-body vibration have an increased risk of preterm birth. Employers should establish supportive workplaces, policymakers implement protective measures, healthcare providers conduct screenings, and pregnant women must stay informed and mitigate these job-related risks. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/], Identifier [CRD42022357045].

The impact of prenatal stressful life events on adverse birth outcomes: A systematic review and meta-analysis

BACKGROUND

Stressful life events as important stressors have gradually been recognized as the potential etiology that may lead to adverse birth outcomes such as preterm birth (PTB), low birth weight (LBW), and small for gestational age (SGA). However, researches on this topic have shown relatively inconsistent results. This systematic review and meta-analysis was performed to synthesize available data on the association between prenatal stressful life events and increased risks of PTB, LBW, and SGA.

METHODS

Electronic databases were searched from their inception until September 2020. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated to assess the association between prenatal stressful life events and PTB, LBW, and SGA using random effects models. In addition, subgroup analyses, cumulative meta-analyses, sensitivity analyses, and publication bias diagnosis were conducted. STATA 14.0 was applied for statistical analyses.

RESULTS

Totally 31 cohort studies involving 5,665,998 pregnant women were included. Prenatal stressful life events were associated with a 20% higher risk of PTB (RR = 1.20, 95%CI = 1.10-1.32), a 23% increased risk for LBW (RR = 1.23, 95%CI = 1.10-1.39), and a 14% higher risk of SGA (RR = 1.14, 95%CI = 1.08-1.20). Sensitivity analysis indicated the results were stable.

CONCLUSIONS

Findings indicated that pregnant women experiencing prenatal stressful life events were at increased risk of PTB, LBW, and SGA. This information provided additional supports that pregnant women experiencing prenatal stressful life events would benefit from receiving assessment and management in prenatal care services.

Gaining a deeper understanding of social determinants of preterm birth by integrating multi-omics data

In the US, high rates of preterm birth (PTB) and profound Black-White disparities in PTB have persisted for decades. This review focuses on the role of social determinants of health (SDH), with an emphasis on maternal stress, in PTB disparity and biological embedding. It covers: (1) PTB disparity in US Black women and possible contributors; (2) the role of SDH, highlighting maternal stress, in the persistent racial disparity of PTB; (3) epigenetics at the interface between genes and environment; (4) the role of the genome in modifying maternal stress-PTB associations; (5) recent advances in multi-omics studies of PTB; and (6) future perspectives on integrating multi-omics with SDH to elucidate the Black-White disparity in PTB. Available studies have indicated that neither environmental exposures nor genetics alone can adequately explain the Black-White PTB disparity. Preliminary yet promising findings of epigenetic and gene-environment interaction studies underscore the value of integrating SDH with multi-omics in prospective birth cohort studies, especially among high-risk Black women. In an era of rapid advancements in biomedical sciences and technologies and a growing number of prospective birth cohort studies, we have unprecedented opportunities to advance this field and finally address the long history of health disparities in PTB. IMPACT: This review provides an overview of social determinants of health (SDH) with a focus on maternal stress and its role on Black-White disparity in preterm birth (PTB). It summarizes the available literature on the interplay of maternal stress with key biological layers (e.g., individual genome and epigenome in response to environmental stressors) and significant knowledge gaps. It offers perspectives that such knowledge may provide deeper insight into how SDH affects PTB and why some women are more vulnerable than others and underscores the critical need for integrating SDH with multi-omics in prospective birth cohort studies, especially among high-risk Black women.

Prenatal stress and child development: A scoping review of research in low- and middle-income countries

INTRODUCTION

Past research has shown relationships between stress during pregnancy, and related psychosocial health measures such as anxiety and depressive symptoms, with infant, child, and adult outcomes. However, most research is from high-income countries. We conducted a scoping review to identify research studies on prenatal stress and outcomes of the pregnancy or offspring in low- and middle-income countries (LMICs), and to synthesize the stress measures and outcomes assessed, the findings observed, and directions for future research.

METHODS

We searched PubMed, Scopus, and PsycINFO for English-language abstracts published from Jan 1960-Jan 2017. Search terms were related to stress and psychosocial health; pregnancy; infant or child development; and LMICs.

RESULTS

48 articles were identified. Sixty percent of studies were in upper-middle, 25% in lower-middle, and 15% in low income countries. Most studies used questionnaires, either existing or tailor-made, to assess stress. Eight assessed cortisol. Most studies (n = 31) assessed infant outcomes at birth, particularly gestational age or preterm birth (n = 22, 12 showing significant relationships), and birthweight (n = 21, 14 showing significant relationships). Five studies analyzed outcomes later in infancy such as temperament and motor development, all showing significant results; and nine in childhood such as behavioral development, asthma, and physical growth, with eight showing significant results.

CONCLUSIONS

Results highlight the importance of prenatal stress on infant and child outcomes in LMICs. Methods used in high-income countries are successfully employed in LMICs, but tailored tools remain necessary. Careful assessment of covariates is needed to foster analyses of interactive effects and pathways. Studies including longer-term follow-up should be prioritized.

Maternal bereavement and the risk of preterm delivery: the importance of gestational age and of the precursor of preterm birth

BACKGROUND

Maternal stress during pregnancy may increase the risk of preterm delivery (PD), but the associations between stress and subtypes of PD are not clear. We investigated maternal loss of a close relative and risks of very and moderately PD (<32 and 32-36 weeks, respectively) and spontaneous and medically indicated PD.

METHOD

We studied 4 940 764 live singleton births in Denmark (1978-2008) and Sweden (1973-2006). We retrieved information on death of women's family members (children, partner, siblings, parents), birth outcomes and maternal characteristics from nationwide registries.

RESULTS

Overall, the death of a close family member the year before pregnancy or in the first 36 weeks of pregnancy was associated with a 7% increased risk of PD [95% confidence interval (CI) 1.04-1.10]. The highest hazard ratios (HR) for PD were found for death of an older child [HR (95% CI) 1.20 (1.10-1.31)] and for death of a partner [HR (95% CI) 1.31 (1.03-1.66)]. These losses were associated with higher risks of very preterm [HR (95% CI) 1.61 (1.29-2.01) and 2.07 (1.15-3.74), respectively] than of moderately preterm [HR (95% CI) 1.14 (1.03-1.26) and 1.22 (0.94-1.58), respectively] delivery. There were no substantial differences in the association between death of a child or partner and the risk of spontaneous v. medically indicated PD.

CONCLUSIONS

Death of a close family member the year before or during pregnancy was associated with an increased risk of PD, especially very PD. Possible mechanisms include both spontaneous and medically indicated preterm birth.

[Relation Between Stress During Pregnancy and Spontaneous Preterm Birth]

BACKGROUND

Preterm birth occurs before 37 completed weeks, its causes are multifactorial and vary according to the gestational age, ethnicity and geographical context. Although several medical/social factors have been clearly identified, over 50% of cases are unknown or unclear; however, psychopathological components emerge as potentially important risk factors.

OBJECTIVE

To determine the relationship between the presence of stress during pregnancy and spontaneous preterm birth.

MATERIAL AND METHODS

Through a study of cases and controls in a level III hospital, with a sample of 360 patients during the period from March to November of 2013, where sociodemographic characteristics were collected. In addition, they were applied scales social adjustment, coping strategies and social support. Logistic regression models were developed; psychological, biological and social. Based on the significant variables in each of these generated a final one.

RESULTS

The final model was found that stress during pregnancy increases the odds of spontaneous preterm birth 1.91 times (adjusted OR=2.91; 95%CI, 1.67-5.08; P<.05). Other significant variables were: history of preterm delivery, unplanned pregnancy, no emotional support, rural residence, inadequate prenatal care and non-stable partner.

CONCLUSIONS

The findings support the hypothesis that stress during pregnancy is associated with spontaneous preterm delivery.

Risk factors for 'small for gestational age babies'

OBJECTIVE

To identify the risk factors for small for gestational age (SGA) babies.

METHODS

The present study was a nested case control study which was carried out by two Medical Officers of Health areas (The field level administrative unit responsible for provision of preventive and promotive health services) in Colombo district. SGA babies were identified using 'weight for gestational age' curves developed for Sri Lankan babies. Newborns of 1,200 pregnant women, who were identified within the first 8 wk of amenorrhea and who delivered in selected hospitals were included in the study. Sample size was calculated as n=167 cases and 4 n=668 controls, with four controls for each case. A case was defined as a newborn whose birth weight was less than the 10th percentile of the weight for gestational age, the control being a newborn whose birth weight was between the 10th and the 90th percentile of the weight for gestational age.

RESULTS

Multivariate analysis identified 7 significant risk factors as, number of live born children=0, inadequate weight gain during pregnancy according to initial BMI, maximum and minimum physical work, mother's pre-pregnant weight less than 38 kg, high level of stress at second trimester, presence of pregnancy induced hypertension (PIH) and inadequate support from husband.

CONCLUSION

The risk factors indicate the directions for planning intervention programs.

Risk of spontaneous preterm birth in relation to maternal experience of serious life events during pregnancy

Background

The purpose of this study was to examine the risk of preterm birth (PTB) in relation to serious life events experienced during pregnancy in Peruvian women.

Methods

This case-control study included 479 PTB cases and 480 term controls. In-person interviews asked information regarding sociodemographics, medical and reproductive histories, and serious life events experienced during pregnancy. Multivariate logistic regression procedures were used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Compared with women who did not experience a serious life event during pregnancy, those who experienced the following life events had a more than two-fold increased odds of PTB: death of first-degree relative (adjusted OR 2.10; 95% CI 1.38–3.20), divorce or separation (adjusted OR 2.09; 95% CI 1.10–4.00), financial troubles (adjusted OR 2.70; 95% CI 1.85–3.94), or serious fight with partner (adjusted OR 2.40; 95% CI 1.78–3.17). Women who experienced any serious life events during pregnancy had higher odds (adjusted OR 2.29; 95% CI 1.65–3.18) of suffering spontaneous preterm labor and preterm premature rupture of membranes (adjusted OR 2.19; 95% CI 1.56–3.08), compared with women who did not experience any such events. Associations of similar directions and extent were observed for severity of PTB (ie, very, moderate, or late PTB). The magnitude of the associations increased as increased frequency of serious life events (P_trend <0.001).

Conclusion

Experiencing serious life events during pregnancy was associated with increased odds of PTB among Peruvian women. Interventions aimed at assisting women experiencing serious life events may reduce the risk of PTB. Future studies should include objective measures of stress and stress response to understand better the biological underpinnings of these associations.

Psychosocial stress in pregnancy and preterm birth: associations and mechanisms

AIMS

Psychosocial stress during pregnancy (PSP) is a risk factor of growing interest in the etiology of preterm birth (PTB). This literature review assesses the published evidence concerning the association between PSP and PTB, highlighting established and hypothesized physiological pathways mediating this association.

METHOD

The PubMed and Web of Science databases were searched using the keywords "psychosocial stress", "pregnancy", "pregnancy stress", "preterm", "preterm birth", "gestational age", "anxiety", and "social support". After applying the exclusion criteria, the search produced 107 articles.

RESULTS

The association of PSP with PTB varied according to the dimensions and timing of PSP. Stronger associations were generally found in early pregnancy, and most studies demonstrating positive results found moderate effect sizes, with risk ratios between 1.2 and 2.1. Subjective perception of stress and pregnancy-related anxiety appeared to be the stress measures most closely associated with PTB. Potential physiological pathways identified included behavioral, infectious, neuroinflammatory, and neuroendocrine mechanisms.

CONCLUSIONS

Future research should examine the biological pathways of these different psychosocial stress dimensions and at multiple time points across pregnancy. Culture-independent characterization of the vaginal microbiome and noninvasive monitoring of cholinergic activity represent two exciting frontiers in this research.

Birth weight, domestic violence, coping, social support, and mental health of young Iranian mothers in Tehran

The aim of this study was to investigate associations of birth weight with sociodemographic variables, domestic violence, ways of coping, social support, and general mental health of Iranian mothers. Six hundred mothers aged 15 to 29 years participated between June 2009 and November 2010. t-Test, analysis of variance, Spearman's correlation, and multiple regression were used. The results showed that there was no significant association between birth weight and general mental health of the mothers. Prenatal care visits, the mothers' history of having children with low birth weight (LBW), and weight gain during pregnancy were significantly associated with birth weight. The women who reported physical abuse during pregnancy had infants with lower birth weight. Satisfaction with social support and use of positive reappraisal were significantly associated with higher birth weight. In conclusion, a high quality of prenatal care and screening of pregnant women are recommended. Social environments good enough during pregnancy have protective effects against LBW.

Work activities and risk of prematurity, low birth weight and pre-eclampsia: an updated review with meta-analysis

OBJECTIVES

We assessed the evidence relating preterm delivery (PTD), low birth weight, small for gestational age (SGA), pre-eclampsia and gestational hypertension to five occupational exposures (working hours, shift work, lifting, standing and physical workload). We conducted a systematic search in Medline and Embase (1966 to 2011), updating a previous search with a further 6 years of observations.

METHODS

As before, combinations of keywords and medical subject headings were used. Each relevant paper was assessed for completeness of reporting and potential for important bias or confounding, and its effect estimates abstracted. Where similar definitions of exposure and outcome existed we calculated pooled estimates of relative risk (RR) in meta-analysis.

RESULTS

Analysis was based on 86 reports (32 cohort investigations, 57 with usable data on PTD, 54 on birth weight and 11 on pre-eclampsia/gestational hypertension); 33 reports were new to this review. For PTD, findings across a substantial evidence base were generally consistent, effectively ruling out large effects (eg, RR>1.2). Larger and higher quality studies were less positive, while meta-estimates of risk were smaller than in previous analyses and best estimates pointed to modest or null effects (RR 1.04 to 1.18). For SGA, the position was similar but meta-estimates were even closer to the null (eight of nine RRs ≤ 1.07). For pre-eclampsia/gestational hypertension the evidence base remains insufficient.

CONCLUSIONS

The balance of evidence is against large effects for the associations investigated. As the evidence base has grown, estimates of risk in relation to these outcomes have become smaller.

The effect of maternal stress and health-related quality of life on birth outcomes among Macao Chinese pregnant women

This study investigated the prevalence of preterm birth and low-birth-weight in Macao. It also evaluated the effects of maternal perceived stress and health-related quality of life on these 2 birth outcomes. A quantitative study using a prospective longitudinal design was undertaken in an antenatal clinic in Macao. A community-based sample (N = 581) of pregnant women in their second trimester was recruited; birth outcome data were collected from medical records. Perceived stress was measured using the Perceived Stress Scale, whereas health-related quality of life was measured using the standard SF-12 Health Survey. The prevalence rates of preterm birth and low-birth-weight were found to be 6.4% and 7.1%, respectively. Two multiple logistic regression analyses revealed that participants with past adverse obstetric complications and higher perceived stress levels were more likely to have premature infants. Also, those participants with higher perceived stress levels and poorer health-related quality of life in the physical health domain were more likely to have low-birth-weight infants. Preliminary information was provided on risk factors associated with adverse birth outcomes; this could help nurses to design appropriate risk-specific interventions for preventing preterm birth and low-birth-weight.