Associations between non-registered ultrasound examination in pregnancy and adverse perinatal outcomes in immigrant and non-immigrant women: a Norwegian population-based study 1999–2016

Compared with non-immigrants, immigrant women had a higher proportion of non-registered ultrasound examinations (2.3% vs. 4.3%; aOR 2.0 (95% CI 1.9, 2.0)). Compared with women with ultrasound examination, the aOR for perinatal mortality for women with non-registered ultrasound was 2.27 (95% CI 1.85, 2.79) for immigrants and 3.61 (3.21, 4.07) for non-immigrants. Non-registered ultrasound examination was also associated with placental abruption (aOR 1.32 (1.08, 1.63)) for non-immigrant women, but it was not associated with preeclampsia.<b>Conclusions:</b><b>Compared with non-immigrants, immigrant women have a higher proportion of non-registered data on prenatal ultrasound examinations. Both immigrants and non-immigrants with non-registered ultrasound examinations have an increased aOR of perinatal mortality. Non-immigrant women also had an increased aOR for placental abruption.</b>