Abstract
Objective To estimate the incidence of placental abruption in immigrant
women compared with non-immigrants by maternal country and region of
birth, reason for immigration and length of residence. Design Nationwide
population-based study. Setting Data from the Medical Birth Registry of
Norway and Statistics Norway (1990-2016). Sample The study sample
included 1,558,174 pregnancies, in which immigrant women accounted for
245,887 pregnancies and 1,312,287 pregnancies were to non-immigrants.
Methods Crude and adjusted odds ratios with 95% confidence intervals
(CI) for placental abruption in immigrant women compared to
non-immigrants were estimated by logistic regression with robust
standard error estimations (accounting for within-mother clustering).
Adjustment variables included year of birth, maternal age, parity,
multiple pregnancies, chronic hypertension and level of education. Main
outcome measures Placental abruption Results The incidence of placental
abruption decreased during the study period for both immigrants (from
0.68% to 0.44%) and non-immigrants (from 0.80% to 0.34%). Immigrant
women from the sub-Saharan African region had an adjusted odds ratio of
1.35 (95% CI: 1.15-1.58) compared to non-immigrants for placental
abruption, whereas immigrant women from Ethiopia had an adjusted odds
ratio of 2.39 (95% CI 1.67-3.41). We found a small variation in
placental abruption incidence by other countries or regions of birth,
length of residence and reason for immigration. Conclusion Immigrant
women from sub-Saharan Africa, especially Ethiopia, have increased odds
for placental abruption when giving birth in Norway. Reason for
immigration and length of residence had little impact on the incidence
of placental abruption.