[Contributions by the investigation of fetal deaths for improving the definition of underlying cause of death in the city of São Paulo, Brazil]

Assessing the risks for stillbirth in São Paulo, Brazil: protocol for a multidisciplinary case-control study - FetRisks

Stillbirth is a fundamental component of childhood mortality, but its causes are still insufficiently understood. This study aims to explore stillbirth risk factors by using a multidisciplinary approach to stimulate public policies and protocols to prevent stillbirth, improve maternal care and support bereaved families. METHODS AND ANALYSIS: In this case-control study with stillbirths and live births in 14 public hospitals in São Paulo, mothers are interviewed at hospitals after delivery, and hospital records and prenatal care registries are reviewed. Maternal and umbilical cord blood samples and placentas are collected to analyse angiogenesis and infection biomarkers, and the placenta's anatomopathological exam. Air pollutant exposure is estimated through the participant's residence and work addresses. Traditional and non-invasive autopsies by image-guided histopathology are conducted in a subset of stillbirths. Subsample mothers of cases are interviewed at home 2 months after delivery on how they were dealing with grief. Information contained in the official prenatal care registries of cases and controls is being compiled. Hospital managers are interviewed about the care offered to stillbirth mothers. Data analysis will identify the main risk factors for stillbirth, investigate their interrelations, and evaluate health services care and support for bereaved families. We hope this project will contribute to the understanding of stillbirth's risk factors and related health services in Brazil, providing new knowledge about this central public health problem, contributing to the improvement of public policies and prenatal and puerperal care, helping to prevent stillbirths and improve the healthcare and support for bereaved families. ETHICS AND DISSEMINATION: This study protocol was approved by the Ethics Committee of the Municipal Health Secretary (process no 16509319.0.3012.5551) and of the Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (process no 16509319.0.0000.0068). Results will be communicated to the study participants, policy-makers and the scientific community.

Prevalence and risk of stillbirth according to biologic vulnerability phenotypes in the municipality of São Paulo, Brazil: A population-based cohort study

OBJECTIVE

To estimate the prevalence and risk of stillbirths by biologic vulnerability phenotypes in a cohort of pregnant women in the municipality of São Paulo, Brazil, 2017-2019.

METHODS

Retrospective population-based cohort study. Fetuses were assessed as small for gestational age (SGA), large for gestational age (LGA), adequate for gestational age (AGA), preterm (PT) as less than 37 weeks of gestation, non-PT (NPT) as 37 weeks of gestation or more, low birth weight (LBW) as less than 2500 g, and non-LBW (NLBW) as 2500 g or more. Relative risks (RR) with robust variance were estimated using Poisson regression.

RESULTS

In all 442 782 pregnancies, including 2321 (0.5%) stillbirths, were included. About 85% (n = 1983) of stillbirths had at least one characteristic of vulnerability, compared with 21% (n = 92524) of live births. Fetuses with all three markers of vulnerability had the highest adjusted RR of stillbirth-SGA + LBW + PT (RR 155.00; 95% confidence interval [CI] 136.29-176.30) and LGA + LBW + PT (RR 262.04; 95% CI 206.10-333.16) when compared with AGA + NLBW + NPT.

CONCLUSION

Our findings show that the simultaneous presence of prematurity, low birth weight, and abnormal intrauterine growth presented a higher risk of stillbirths. To accelerate progress towards reducing preventable stillbirths, one must identify the circumstances of greatest biologic vulnerability.

Intra-urban differentials of fetal mortality in clusters of social vulnerability in São Paulo Municipality, Brazil

This study aimed to analyze the distribution of stillbirths by birth weight, type of death, the trend of Stillbirth Rate (SBR), and avoidable causes of death, according to social vulnerability clusters in São Paulo Municipality, 2007-2017. Social vulnerability clusters were created with the k-means method. The Prais-Winsten generalized linear regression was used in the trend of SBR by < 2500 g,  ≥ 2500 g, and total deaths analysis. The Brazilian list of avoidable causes of death was adapted for stillbirths. There was a predominance of antepartum stillbirths (70%). There was an increase in SBR with the growth of social vulnerability from the center to the outskirts of the city. The cluster with the highest vulnerability presented SBR 69% higher than the cluster with the lowest vulnerability. SBR ≥ 2500 g was decreasing in the clusters with the high vulnerability. There was an increase in SBR of avoidable causes of death of the cluster from the lowest to the highest vulnerability. Ill-defined causes of death accounted for 75% of deaths in the highest vulnerability area. Rates of fetal mortality and avoidable causes of death increased with social vulnerability. The trend of reduction of SBR ≥ 2500 g may suggest improvement in prenatal care in areas of higher vulnerability.