BJOG: An International Journal of Obstetrics and Gynaecology BJOG: An International Journal of Obstetrics and Gynaecology, 2021, Online ahead of print. ⟨10.1111/1471-0528.16892⟩ BJOG: An International Journal of Obstetrics and Gynaecology, Wiley, 2021, Online ahead of print. ⟨10.1111/1471-0528.16892⟩