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

Prenatal Exposure to Severe Stress and the Risk of Heart Failure Up to Middle-Age

BACKGROUND

Prenatal stress is a potential risk factor for cardiovascular disease, but its association with heart failure (HF) is unknown.

OBJECTIVES

The purpose of this study was to investigate whether prenatal stress, defined as maternal bereavement, was associated with HF risk up to middle-age.

METHODS

This cohort study included 6,758,560 live singleton births from the Danish (1973-2016) and the Swedish (1973-2014) Medical Birth Registers. The authors retrieved information on death of the mothers' close family members (partner, older children, parents, and siblings) and offspring's HF (up to 2016 in Denmark and 2020 in Sweden) from nationwide registers. They estimated HRs and 95% CIs for HF in the offspring according to maternal bereavement.

RESULTS

During up to 48 years of follow-up, 4,812 offspring (0.07%) had a diagnosis of HF. Maternal loss of any close family member was not associated with HF in the offspring (adjusted HR: 1.04; 95% CI: 0.88-1.23). However, the most severe forms of bereavement, ie, death of a partner or an older child (adjusted HR: 1.47; 95% CI: 1.06-2.04) and unnatural death of a relative (adjusted HR: 2.77; 95% CI: 1.49-5.17), were associated with increased risks of HF. Congenital heart disease and preterm birth contributed substantially to the association of maternal loss of a partner or older child with HF risk in the offspring.

CONCLUSIONS

Maternal loss of a partner or older child and loss of a close relative caused by unnatural causes the year before or during pregnancy were associated with increased risk of HF in offspring.

Prenatal Exposure to Severe Stress and Risks of Ischemic Heart Disease and Stroke in Offspring

Importance

Prenatal stress is associated with increased risks of several cardiovascular risk factors later in life. However, knowledge regarding the role of prenatal stress in the development of ischemic heart disease (IHD) and stroke is very limited.

Objective

To examine prenatal stress, defined as maternal bereavement, and risks of IHD and stroke in the offspring.

Design, Setting, and Participants

A cohort study was conducted using data from Danish and Swedish registries. Live singleton births during calendar years 1973-2016 in Denmark (followed up until December 31, 2016) and during calendar years 1973-2014 in Sweden (followed up until December 31, 2021) were included in the analysis.

Exposure

Maternal loss of a close family member (partner, older children, parents, or siblings) the year before or during the pregnancy.

Main Outcome and Measures

Diagnoses of IHD and stroke. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% CIs for IHD and stroke in the offspring according to maternal bereavement.

Results

The study included 6 758 560 births (39.4% from Denmark; 51.4% boys). During the median follow-up of 24.6 (IQR, 13.9-35.1) years, 8664 offspring (0.1%) were diagnosed with IHD and 13 094 with stroke (0.2%). Overall, maternal bereavement the year before or during pregnancy was not associated with IHD (adjusted HR [AHR], 0.98; 95% CI, 0.85-1.13) or stroke (AHR, 1.04; 95% CI, 0.94-1.16) in offspring. Similarly, no associations were observed when exposure was classified by the mother's relationship to the deceased individual, ie, loss of older child or partner (HR, 0.85; 95% CI, 0.64-1.14 for IHD and 0.98; 95% CI, 0.77-1.25 for stroke) or loss of parent or sibling (HR, 1.03; 95% CI, 0.87-1.21 for IHD and 1.06; 95% CI, 0.94-1.19 for stroke). However, associations between loss in the third trimester and IHD (AHR, 1.50; 95% CI, 1.06-2.13), and loss due to cardiovascular disease and stroke (AHR, 1.22; 95% CI, 1.03-1.44) were identified when exposure was classified by time of loss or the relative's cause of death.

Conclusions and Relevance

The findings of this study provide little support for the hypothesis that prenatal stress is associated with risks of IHD and stroke in the first 5 decades of life. However, the association observed between stress in the third trimester and IHD warrants further investigation.

Maternal Bereavement the Year Before or During Pregnancy and Total and Cause-Specific Infant Mortality: A Cohort Study From Denmark and Sweden

OBJECTIVE

We analyzed the associations between maternal bereavement the year before or during pregnancy and total and cause-specific infant mortality (IM).

METHODS

We studied live singleton births from the Danish (1978-2008) and Swedish Medical Birth Registers (1973-2006; N = 5,114,246). Information on maternal sociodemographic, pregnancy-related, and health-related factors, and death of family members was obtained from nationwide registers.

RESULTS

Among children of mothers with register links to family members and without the considered IM risk factors, 110,993 (2.76%) were exposed and 15,199 (0.4%) died in infancy. Death of an older child the year before or during pregnancy was associated with an increased IM risk (adjusted odds ratio [aOR; 95% confidence intervals {CIs}] = 2.05 [1.44-2.92]). Losing an older child the year before pregnancy or during pregnancy was associated with risks of prematurity-related IM (aOR [95% CI] = 2.61 [1.44-4.72] and 3.08 [1.70-5.57]) and with infant death in term-born children due to causes other than sudden infant death syndrome, congenital malformations, or asphyxia (aOR [95% CI] = 3.31 [1.58-6.96] and 5.10 [1.27-20.43]). Losing an older child during pregnancy was also associated with increased risks of sudden infant death syndrome (aOR [95% CI] = 5.41 [1.34-21.83]). Death of a partner during pregnancy was associated with IM (aOR [95% CI] = 1.83 [1.01-3.32]). The number of events was small and CIs were wide in some subanalyses, and caution is needed when interpreting our results.

CONCLUSIONS

Severe prenatal stress may increase the risk of several types of IM. Whether less severe but more common maternal stressors shortly before or during pregnancy also increase IM risk warrants further investigation.

Adverse Pregnancy Outcomes Following the Assassination of John F. Kennedy in 1963

INTRODUCTION

Women exposed to stressful events during pregnancy are thought to be at increased risk of adverse birth outcomes. However, studies investigating stressful events are often unable to control for important confounders, such as behavioral and genetic characteristics, or to isolate the impact of the stressor from other secondary effects. We used a discordant-sibling design, which provides stronger inferences about causality, to examine whether a widespread stressor with limited impact on day-to-day life (John F. Kennedy assassination) resulted in an increased risk of adverse birth outcomes.

METHODS

Data were obtained from the Collaborative Perinatal Project, a prospective, multi-site cohort study conducted in the US from 1959 to 1965. Our analysis was restricted to singleton live births ≥24 weeks born before the assassination (n = 24,406) or in utero at the time (n = 5833). We also evaluated associations within siblings discordant for exposure (n = 1144). We used survival analysis to evaluate associations between exposure and preterm birth and marginal models to evaluate associations with birthweight and placental pathology.

RESULTS

First trimester exposure was associated with preterm birth (hazard ratio (HR): 1.17; 95% CI: 1.05, 1.31). In the discordant-sibling model, the point estimate was similar (HR: 1.22; 95% CI: 0.36, 4.06). Third trimester exposure was associated with increased odds of fetal acute inflammation in the placenta (odds ratio (OR): 1.34, 95% CI: 1.05, 1.71).

CONCLUSIONS FOR PRACTICE

First trimester exposure to an acute stressor was associated with preterm birth. We did not observe increased odds of placental pathology with first trimester exposure; however, stress may increase preterm birth risk through chronic placental inflammation, which was not evaluated in this sample.

Stressors Across the Life-Course and Preterm Delivery: Evidence From a Pregnancy Cohort

Objectives Growing evidence suggests that pre-conception stressors are associated with increased risk of preterm delivery (PTD). Our study assesses stressors in multiple domains at multiple points in the life course (i.e., childhood, adulthood, within 6 months of pregnancy) and their relation to PTD. We also examine heterogeneity of associations by race/ethnicity, PTD timing, and PTD clinical circumstance. Methods We assessed stressors retrospectively via mid-pregnancy questionnaires in the Pregnancy Outcomes and Community Health Study (1998-2004), a Michigan pregnancy cohort (n = 2559). Stressor domains included abuse/witnessing violence (hereafter "abuse"), loss, economic stress, and substance use. We used logistic and multinomial regression for the following outcomes: PTD (<37 weeks' gestation), PTD by timing (≤34 weeks, 35-36 weeks) and PTD by clinical circumstance (medically indicated, spontaneous). Covariates included race/ethnicity, education, parity, and marital status. Results Stressors in the previous 6 months were not associated with PTD. Experiencing abuse during both childhood and adulthood increased adjusted odds of PTD among women of white or other race/ethnicity only (aOR 1.6, 95 % CI 1.1, 2.5). Among all women, abuse in childhood increased odds of late PTD (aOR 1.5, 95 % CI 1.0, 2.2) while abuse in both childhood and adulthood non-significantly increased odds of early PTD (aOR 1.6, 95 % CI 0.9, 2.7). Sexual, but not physical, abuse in both childhood and adulthood increased odds of PTD (aOR 1.9, 95 % CI 1.0, 3.5). Conclusions Experiences of abuse-particularly sexual abuse-across the life-course may be important considerations when assessing PTD risk. Our results motivate future studies of pathways linking abuse and PTD.

Prenatal maternal bereavement and mortality in the first decades of life: a nationwide cohort study from Denmark and Sweden

BACKGROUND

The loss of a close relative is one of the most stressful life events. In pregnancy, this experience has been associated with a higher risk of fetal death and under-five mortality, but little is known about potential effects on long-term mortality in offspring. We examined the association between prenatal maternal bereavement and mortality in a cohort of 5.3 million children followed until up to 37 years of age.

METHOD

The population-based cohort study included 5 253 508 live singleton births in Denmark (1973-2004) and Sweden (1973-2006). Children born to mothers who lost a child, spouse, sibling, or parent during or 1 year before pregnancy were categorized as exposed.

RESULTS

Prenatal maternal bereavement was associated with a 10% increased all-cause mortality risk in offspring [mortality rate ratio (MRR) 1.10, 95% confidence interval (CI) 1.03-1.18]. The association was the most pronounced for children of mothers who lost a child/spouse (MRR 1.28, 95% CI 1.14-1.44) and was stronger during the first 10 years of life. Prenatal maternal bereavement may have stronger effects on natural causes of death in offspring, including infectious/parasitic disease (MRR 1.86, 95% CI 1.07-3.23), endocrine/nutritional/metabolic diseases (MRR 3.23, 95% CI 2.02-5.17), diseases of nervous system (MRR 3.36, 95% CI 2.47-4.58), and congenital malformations (MRR 1.39, 95% CI 1.08-1.80). No excess mortality risk in offspring was observed for unnatural causes of death.

CONCLUSION

Prenatal maternal bereavement was associated with an increased long-term mortality risk in offspring, particularly for selected natural causes of diseases and medical conditions. Our results support the fetal programming hypothesis that prenatal stress may contribute to ill health from physical diseases later in life.