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, Ma over bar ori 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 experi-enced 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 Ma over bar ori 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 Ma over bar ori 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.

Automated summary

Women of South Asian ethnicity in Aotearoa NZ have a higher risk of adverse pregnancy outcomes, including placental dysfunction and antepartum haemorrhage compared to NZ European and Maori women. Placental pathology differences were observed among perinatal deaths between 20+0 to 27+6 weeks gestation, with South Asian women more likely to show features of histologic chorioamnionitis and chorionic vasculitis. Metabolic disorders and an associated pro-inflammatory environment may contribute to these differences.