Secular trends in stillbirth by maternal socioeconomic status in Spain 2007-15: a population-based study of 4 million births

Preterm birth and stillbirth rates associated with socioeconomic disparities during COVID-19 pandemic: a population-based cross-sectional study

BACKGROUND

Conflicting evidence exists on the impact of the COVID-19 pandemic restrictions on preterm birth (PTB) and stillbirth rates. We aimed to evaluate changes in PTB and stillbirth rates before and during the pandemic period and assess the potential effect modification of socioeconomic status (SES).

METHODS

Using the linked administrative health databases from Manitoba, Canada, we conducted a cross-sectional study among all pregnant women, comparing 3.5 years pre-pandemic (1 October 2016 to 29 February 2020) to the first year of the pandemic (1 March 2020 to 31 March 2021). We used generalised linear models to assess the quarterly rates of PTB (<37 weeks) and stillbirths. We calculated the predicted trends based on pre-pandemic period data. Finally, we evaluated the PTB and stillbirth rates among lower and higher SES pregnant women (average annual household income) using subgroup analysis and interaction models.

RESULTS

We examined 70 931 pregnancies in Manitoba during the study period. The risk of PTB increased by 7.7% (95%CI 1.01 to 1.13) and stillbirths by 33% (95% CI 1.08 to 1.64) during the pandemic period. Following COVID-19 restrictions implemented in March 2020, there were increases in the quarterly rates of both PTB (immediate increase (β2)=1.37; p=0.0247) and stillbirths (immediate increase (β2)=0.12; p=0.4434). Among the lower income groups, the pandemic restrictions resulted in an immediate relative increase in PTB and stillbirth rates by 20.12% (immediate increase (β2)=3.17; p=0.0057) and 27.19% (immediate increase (β2)=0.48; p=0.0852). However, over the pandemic, the overall PTB rate significantly decreased as a rebound effect by 0.85% per quarter (p=0.0004), whereas the overall stillbirth rate did not decrease significantly (slope decrease (β3) =-0.01; p=0.8296) compared with the pre-pandemic period. The quarterly rates during the pandemic among the higher income group decreased by 0.39% (p=0.1296) for PTB and increased by 0.07% (p=0.1565) for stillbirth. We observed an effect modification by SES for PTB rates (p=0.047).

CONCLUSION

While the onset of COVID-19 pandemic restrictions was not associated with significant effects on stillbirth rates, we observed an immediate and rebound effect on PTB rates. The impact of COVID-19 on preterm birth was dependent on SES, with higher influence on families with lower SES. Further studies are needed to detect future trend changes during pandemic waves after 2021 and assess potential underlying mechanisms.

Relationship between historical developments in the percentages of low birthweight and fetal mortality in Spain

OBJECTIVE

To document the differences in low birthweight in different population subgroups and to analyze its possible relationship with fetal mortality rates in Spain.

METHOD

We used the microdata on live births and stillbirths since 1975 to 2020 from the Spanish National Statistics Institute to examine differentials in delivering a low birthweight controlling for different sociodemographic variables and to determine the relationship between low birthweight and fetal mortality. No statistical analysis was necessary beyond the calculation of percentages and rates.

RESULTS

The data at our disposal for Spain confirm the historical increase in the incidence of low birthweight and allow us to link trends in low birthweight with a decrease in the fetal mortality rate. When fetal mortality is high, the incidence of low birthweight is low, given that a natural selection effect takes place.

CONCLUSIONS

The surprising historical increase in the incidence of low birthweight in Spain can be explained by the improvement in mortality rates. As more fetuses of lower gestational age are born alive, cases of low birthweight also increase.

Spatial dynamics of fetal mortality and the relationship with social vulnerability

OBJECTIVES

To analyze the spatial-temporal patterns of fetal mortality according to its relationship with social vulnerability, identifying priority areas for intervention.

METHODS

Ecological study conducted in the state of Pernambuco, Northeast region of Brazil, from 2011 to 2018. The mean fetal mortality rate per city was calculated for the studied period. A cluster analysis was performed to select cities with homogeneous characteristics regarding fetal mortality and social vulnerability, then the Attribute Weighting Algorithm and Pearson correlation techniques were employed. In the spatial analysis it was used the local empirical Bayesian modeling and global and local Moran statistics.

RESULTS

Twelve thousand nine hundred and twelve thousand fetal deaths were registered. The fetal mortality rate for the period was 11.44 fetal deaths per 1,000 births. The number of groups formed was 7, in which correlation was identified between fetal mortality and dimensions, highlighting the correlations between fetal mortality rate and the Index of Social Vulnerability urban infrastructure for the municipalities in group 1 and 5, the values of the correlations found were 0.478 and 0.674 respectively. The spatial analysis identified areas of higher risk for fetal mortality distributed in regions of medium, high and very high social vulnerability.

CONCLUSIONS

The study allowed observing the existing correlations between fetal mortality and social vulnerability and identifying priority areas for intervention, with a view to reducing fetal mortality in the state.

Blood pressure and hypertensive disorders of pregnancy at high altitude: a systematic review and meta-analysis

OBJECTIVE

Exposure to high altitude (≥2500 m) is associated with increased arterial blood pressure. During pregnancy, even a mild elevation of maternal blood pressure is associated with reduced birthweight and increased prevalence of pregnancy complications. This study aimed to systematically assess the impact of altitude on maternal blood pressure at term and on the prevalence of hypertensive disorders of pregnancy.

DATA SOURCES

PubMed, Ovid Embase, Cochrane Library, Medline, Web of Science, and ClinicalTrials.gov were searched (inception to November 11, 2020).

STUDY APPRAISAL AND SYNTHESIS METHODS

Observational, cohort, or case-control studies were included if they reported a high-altitude and appropriate control pregnant population. Studies published >50 years ago were excluded; 2 reviewers independently assessed articles for eligibility and risk of bias.

RESULTS

At high altitude, maternal systolic and diastolic blood pressure at term was higher than at low altitude (4.8±1.6 mm Hg; P<.001; 4.0±0.8 mm Hg; P<.001, respectively). Hypertensive disorders of pregnancy were more common at high altitude (odds ratio, 1.31 [1.03-1.65]; P<.05). The prevalence of gestational hypertension was nearly twice as high at high altitude (odds ratio, 1.92 [1.15-3.22]; P<.05) but the prevalence of preeclampsia was half as high (odds ratio, 0.57 [0.46-0.70]; P<.001). The likelihood of stillbirth was increased by 63% in pregnancies at high altitude compared with low altitude (odds ratio, 1.63 [1.12-2.35]; P<.01).

CONCLUSION

Maternal blood pressure is higher at term in pregnancies at high altitude than low altitude, accompanied with an increased risk of gestational hypertension but not preeclampsia. Risk of stillbirth at high altitude is also increased. With a growing population residing at high altitude worldwide, it is essential to clearly define the associated risk of adverse pregnancy outcomes.

Health indicators of the National Roma Integration Strategy in Spain in the years 2006 and 2014

BACKGROUND

In 2011, the European Commission adopted the European framework for the National Roma Integration Strategies (NRISs) 2020, which focussed on four areas: education, employment, health and housing. In 2012 Spain approved its Strategy 2012-20, one of the central aims of which is to reduce social inequalities in health that affect the Roma population. Our objective was to analyze changes in health inequalities between the Roma population and the general population in Spain in the years 2006 and 2014.

METHODS

The Spanish National Health Surveys (NHSs) 2006 (n = 29 478) and 2012 (n = 20 884) and the NHS of the Spanish Roma Population 2006 (n = 933) and 2014 (n = 1155) were compared. This study considered the variables included in NRIS 2012-20: self-perceived health, tobacco use in men, traffic accidents in men and women, obesity in women and gynaecological visits.

RESULTS

Despite the adoption of the NRIS 2012-20, there were no observed improvements in health between 2006 and 2014 in the Roma population. Nor was there a reduction in inequalities in health concerning the general population in Spain. Also, there was no reduction in the health inequalities by gender for the two populations.

CONCLUSIONS

Health is determined in part by social factors including education, employment, housing and also by anti-Roma discourses and discrimination. Improving the health of the Roma population requires a multi-sectoral approach with a gender perspective.

Spatial patterns of avoidable fetal mortality and social deprivation

OBJECTIVE

To develop a social need index for stratification of municipalities and identification of priority areas for reducing fetal mortality.

METHODS

ecological study, carried out in the state of Pernambuco, between 2010 and 2017. The technique of factor analysis by main components was used for the elaboration of the social need index. In the spatial analysis, the local empirical Bayesian estimator was applied and Moran's spatial autocorrelation was verified.

RESULTS

The social deprivation index selected two factors that, together, explained 77.63% of the total variance. The preventable fetal mortality rate increased among strata of social need, with rates of 8.0 per thousand births (low deprivation), 8.1 per thousand (medium deprivation), 8.8 per thousand (high deprivation), and 10.7 per thousand (very high social deprivation). Some municipalities in the São Francisco and Sertão Mesoregions had both high fetal and preventable fetal mortality, in addition to a very high social deprivation rate. Conclusion: The spatial analysis identified areas with the highest risk for fetal mortality. The social deprivation index listed some determinants of fetal deaths in areas with worse living conditions. Priority areas for intervention in public policies to reduce fetal mortality and its determinants were detected.

Fetal and infant mortality trends according to the avoidability of causes of death and maternal education

OBJECTIVE

To estimate trends of fetal (FMR) and neonatal (NMR) mortality rates due to avoidable causes and maternal education in the city of Rio de Janeiro (2000-2018).

METHODS

Ecological time series study. Mortality and Live Birth Information System Data. The List of Avoidable Causes of Death Due to Interventions of the Brazilian Health System was used for neonatal deaths and an adaptation for fetal deaths, according to maternal education indicators (low <4 and high ≥12, years of study). Joinpoint regression models were used to estimate trends in FMR, based on one thousand births, and NMR, based on one thousand live births.

RESULTS

FMR decreased from 11.0 to 9.3% and NMR from 11.3 to 7.8% (2000/2018). In 2006, FMR (10.5%) exceeded NMR (9.0%), remaining higher. From 2000 to 2018, the annual decrease of FMR was 0.8% (2000 to 2018) and of NMR, 3.8% until 2007, decreasing to 1.1% by 2011; from then on, it remained stable. Avoidable causes, especially those reducible by adequate prenatal care, showed higher rates. Both FMR and NMR for low-education women were higher than those for the high-education level, the difference being much more pronounced for FMR, and at the end of the period: low- and high-education FMR were respectively 16.4 and 4.5% (2000) and 48.5 and 3.9% (2018), and for NMR, 18.2 and 6.7% (2000) and 28.4 and 5.0% (2018).

CONCLUSION

The favorable trend of decreasing mortality was not observed for children of mothers with low education, revealing inequalities. The causes were mostly avoidable, being related to prenatal care and childbirth.

Risk of Stillbirth Among Foreign-Born Mothers in the United States

The objective of this study is to assess the impact of maternal nativity on stillbirth in the US. We utilized the US Birth Data and Fetal Death Data for the years 2014-2017. Our analysis was restricted to live and stillbirths (N= of 14,867,880) that occurred within the gestational age of 20-42 weeks. The fetuses-at risk approach was used to generate stillbirth trends by gestational age. Adjusted Cox proportional hazards regression model was utilized to estimate the association between maternal nativity and stillbirth. Overall, the gestational week-specific prospective risk of stillbirth was consistently higher for native-born than their foreign-born mothers. Foreign-born mothers were 20% less likely to experience stillbirth than their native-born counterparts (AHR = 0.80; 95% CI = 0.78-0.81). Delineating the factors influencing the observed effect of maternal nativity on birth outcomes should be a research priority to inform strategies to address adverse birth outcomes in the US.

Human Development Index of the maternal country of origin and its relationship with maternal near miss: A systematic review of the literature

Background

The reduction in maternal mortality worldwide has increased the interest in studying more frequent severe events such as maternal near miss. The Human Development Index is a sociodemographic country-specific variable that includes key human development indicators such as living a long and healthy life, acquiring knowledge, and enjoying a decent standard of living, allowing differentiation between countries. In a globalised environment, it is necessary to study whether the Human Development Index of each patient's country of origin can be associated with the maternal near-miss rate and thus classify the risk of maternal morbidity and mortality.

Methods

A systematic review of the literature published between 2008 and 2019 was conducted, including all articles that reported data about maternal near miss in their sample of pregnant women, in addition to describing the study countries of their sample population. The Human Development Index of the study country, the maternal near-miss rate, the maternal mortality rate, and other maternal-perinatal variables related to morbidity and mortality were used.

Results

After the systematic review, eighty two articles from over thirty countries were included, for a total of 3,699,697 live births, 37,191 near miss cases, and 4029 mortality cases. A statistically significant (p <0.05) inversely proportional relationship was observed between the Human Development Index of the study country and the maternal near-miss and mortality rates. The most common cause of maternal near miss was haemorrhage, with an overall rate of 38.5%, followed by hypertensive disorders of pregnancy (34.2%), sepsis (7.5%), and other undefined causes (20.9%).

Conclusions

The Human Development Index of the maternal country of origin is a sociodemographic variable allowing differentiation and classification of the risk of maternal mortality and near miss in pregnant women. The most common cause of maternal near miss published in the literature was haemorrhage.

Trial registration

PROSPERO ID: CRD 42019133464