Risk of stillbirth and preterm birth among undocumented pregnant migrant women in Denmark: A retrospective case-control study

Aims: To examine the associations between undocumented pregnant migrant women and the risk of experiencing stillbirth or preterm birth. Methods: A retrospective case-control study based on nationwide registers from Statistics Denmark and hospital journals from the seven largest hospital wards in Denmark from 1 January 2011 to 31 December 2018. A total of 882 undocumented pregnant migrant women and 3528 matched controls (both documented migrant and non-migrant women) were included. Logistic regression models were used to estimate the risk of undocumented pregnant migrant women experiencing (a) stillbirth and (b) preterm birth compared with the control group. Results: Of the undocumented pregnant migrant women, 33.3% were EU citizens, 16.2% were applicants for residence and 50.5% had an unknown basis for residence. The mean age of the undocumented pregnant migrant women was 28.4 years, whereas the mean age of women in the control group was 30.9 years. Higher adjusted odds of experiencing stillbirth (aOR 3.50; 95% CI 1.31-9.38) and preterm birth (aOR 1.41; 95% CI 1.04-1.93) were observed among the undocumented pregnant migrant women compared with the control group. The basis of residence was not associated with higher odds of experiencing stillbirth or preterm birth. Conclusions: We found a higher risk of stillbirth and preterm birth among the undocumented pregnant migrant women than in the control group. Our findings suggest a need to increase the focus on providing access to antenatal care among those women currently excluded from this care.