Ethnic variation in causes of stillbirth in high income countries: A systematic review and meta-analysis

Causes of stillbirth in ethnically diverse women in a Perth metropolitan hospital: A retrospective study

BACKGROUND

Most published reports analysing the differences in causation of stillbirth between different ethnic groups focus on stillbirth risk factors, with a paucity of data comparing actual causes of stillbirth.

AIMS

To determine whether causes of stillbirth differ between Caucasian and non-Caucasian ethnic groups in an Australian context.

MATERIALS AND METHODS

Data from all stillbirths occurring at 20 or more completed weeks of gestation between 1 January 2010 and 31 December 2020 at a secondary level, outer metropolitan hospital, were analysed in this retrospective case series. Causes of stillbirth as determined by perinatal autopsy and placental histopathology were categorised using the Perinatal Society of Australia and New Zealand Perinatal Death Classification and compared between Caucasian and non-Caucasian groups.

RESULTS

Ninety-two stillbirths (0.7% of all births) were identified during the study period. A greater proportion of non-Caucasian women had small for gestation age placentas compared to Caucasian women (n = 22/43 (51%) vs n = 12/49 (24%); P = 0.025). A greater proportion of stillbirths were caused by hypoxic peripartum death in non-Caucasian than in Caucasian women (n = 4/43 (9%) vs n = 0/49 (0%); P = 0.044), and a greater prevalence of placental dysfunction was seen in the non-Caucasian cohort compared to Caucasian women (n = 14/43 (33%) vs n = 8/49 (16%); P = 0.057).

CONCLUSIONS

The differences observed in causes of stillbirth between Caucasian and non-Caucasian women are hypothesis generating and warrant further larger-scale, multi-centred studies using standardised definitions and classification systems to determine whether these differences persist in a more representative sample.

Racial and ethnic inequities in stillbirth in the US: Looking upstream to close the gap: Seminars in Perinatology

Though stillbirth rates in the United States improved over the previous decades, inequities in stillbirth by race and ethnicity have persisted nearly unchanged since data collection began. Black and Indigenous pregnant people face a two-fold greater risk of experiencing the devastating consequences of stillbirth compared to their White counterparts. Because race is a social rather than biological construct, inequities in stillbirth rates are a downstream consequence of structural, institutional, and interpersonal racism which shape a landscape of differential access to opportunities for health. These downstream consequences can include differences in the prevalence of chronic health conditions as well as structural differences in the quality of health care or healthy neighborhood conditions, each of which likely plays a role in racial and ethnic inequities in stillbirth. Research and intervention approaches that utilize an equity lens may identify ways to close gaps in stillbirth incidence or in responding to the health and socioemotional consequences of stillbirth. A community-engaged approach that incorporates experiential wisdom will be necessary to create a full picture of the causes and consequences of inequity in stillbirth outcomes. Investigators working in tandem with community partners, utilizing a combination of qualitative, quantitative, and implementation science approaches, may more fully elucidate the underpinnings of racial and ethnic inequities in stillbirth outcomes.

Placental pathology findings in perinatal deaths from 28 weeks gestation in Aotearoa New Zealand

INTRODUCTION

Women of South Asian ethnicity are overrepresented in adverse pregnancy outcome across high-income countries, including those related to placental dysfunction. It has been hypothesised that placental aging occurs at earlier gestation in South Asian pregnancies. We aimed to identify differences in placental pathology among perinatal deaths ≥28 weeks gestation, between South Asian, Māori and New Zealand (NZ) European women in Aotearoa NZ, with a focus on women of South Asian ethnicity.

METHODS

Placental pathology reports and clinical data from perinatal deaths between 2008 and 2017 were provided by the NZ Perinatal and Maternal Mortality Review Committee, blinded, and analysed by an experienced perinatal pathologist using the Amsterdam Placental Workshop Group Consensus Statement criteria.

RESULTS

790 of 1161 placental pathology reports, 346 preterm (28⁺⁰ to 36⁺⁶ weeks) and 444 term (≥37⁺⁰ weeks) deaths, met the inclusion criteria. Among preterm deaths, South Asian women had higher rates of maternal vascular malperfusion compared with Māori (aOR 4.16, 95%CI 1.55-11.15) and NZ European (aOR 2.60, 95%CI 1.10-6.16). Among term deaths, South Asian women had higher rates of abnormal villous morphology compared with Māori (aOR 2.19, 95%CI 1.04-4.62) and NZ European (aOR 2.12, 95%CI 1.14-3.94), mostly due to increased rates of chorangiosis (36.7%, compared to 23.3% and 21.7%, respectively).

DISCUSSION

Differences in placental pathology by ethnicity were observed among preterm and term perinatal deaths. While we suspect differing underlying causal pathways, these deaths may be associated with maternal diabetic and red blood cell disorders among South Asian women, leading to a hypoxic state in-utero.

Placental pathology findings amongst extremely preterm perinatal deaths in Aotearoa New Zealand

INTRODUCTION

Women of South Asian ethnicity are overrepresented in adverse pregnancy outcomes across high-income countries, including placental dysfunction and antepartum haemorrhage. As the burden of mortality is highest for extremely preterm infants, we aimed to identify any differences in placental pathology among perinatal deaths from 20⁺⁰ to 27⁺⁶ weeks gestation between South Asian, Māori and New Zealand (NZ) European women in Aotearoa NZ, with a focus on women of South Asian ethnicity.

METHODS

Placental pathology reports and clinical data from perinatal deaths between 2008 and 2017 were provided by the NZ Perinatal and Maternal Mortality Review Committee, blinded and analysed by an experienced perinatal pathologist using the Amsterdam Placental Workshop Group Consensus Statement criteria. South Asian ethnicity was classified as Indian, Fijian Indian, South African Indian, Sri Lankan, Pakistani and Bangladeshi.

RESULTS

886 of 1571 placental pathology reports met the inclusion criteria. Women of South Asian ethnicity were significantly more likely to show features of histologic chorioamnionitis (aOR 1.87, 95%CI 1.19-2.94) and chorionic vasculitis (aOR 1.92, 95%CI 1.13-3.29), than NZ European and Māori women respectively. 13 of 15 (87%) of South Asian mothers with a diabetic disorder were identified with chorioamnionitis, compared to 1 in 5 (20%) of Māori and 5 in 12 (41%) of NZ European women. Cord hyper-coiling was also more common among South Asian pregnancies, compared to NZ European (aOR 1.98, 95%CI 1.10-3.56).

DISCUSSION

Differences in placental pathology by ethnicity were observed among extremely preterm perinatal deaths. Underlying metabolic disorders and an associated pro-inflammatory environment may play an important role in the causal pathway leading to these deaths in women of South Asian ethnicity.

Vitamin D deficiency in British South Asians, a persistent but avoidable problem associated with many health risks (including rickets, T2DM, CVD, COVID-19 and pregnancy complications): the case for correcting this deficiency

High vitamin D deficiency rates, with rickets and osteomalacia, have been common in South Asians (SAs) arriving in Britain since the 1950s with preventable infant deaths from hypocalcaemic status-epilepticus and cardiomyopathy. Vitamin D deficiency increases common SA disorders (type 2 diabetes and cardiovascular disease), recent trials and non-linear Mendelian randomisation studies having shown deficiency to be causal for both disorders. Ethnic minority, obesity, diabetes and social deprivation are recognised COVID-19 risk factors, but vitamin D deficiency is not, despite convincing mechanistic evidence of it. Adjusting analyses for obesity/ethnicity abolishes vitamin D deficiency in COVID-19 risk prediction, but both factors lower serum 25(OH)D specifically. Social deprivation inadequately explains increased ethnic minority COVID-19 risks. SA vitamin D deficiency remains uncorrected after 70 years, official bodies using 'education', 'assimilation' and 'diet' as 'proxies' for ethnic differences and increasing pressures to assimilate. Meanwhile, English rickets was abolished from ~1940 by free 'welfare foods' (meat, milk, eggs, cod liver oil), for all pregnant/nursing mothers and young children (<5 years old). Cod liver oil was withdrawn from antenatal clinics in 1994 (for excessive vitamin A teratogenicity), without alternative provision. The take-up of the 2006 'Healthy-Start' scheme of food-vouchers for low-income families with young children (<3 years old) has been poor, being inaccessible and poorly publicised. COVID-19 pandemic advice for UK adults in 'lockdown' was '400 IU vitamin D/day', inadequate for correcting the deficiency seen winter/summer at 17.5%/5.9% in White, 38.5%/30% in Black and 57.2%/50.8% in SA people in representative UK Biobank subjects when recruited ~14 years ago and remaining similar in 2018. Vitamin D inadequacy worsens many non-skeletal health risks. Not providing vitamin D for preventing SA rickets and osteomalacia continues to be unacceptable, as deficiency-related health risks increase ethnic health disparities, while abolishing vitamin D deficiency would be easier and more cost-effective than correcting any other factor worsening ethnic minority health in Britain.