Risk factors for blood transfusion at delivery in Finland.
OBJECTIVE
To examine the prevalence and risk factors for blood transfusion during delivery.


METHODS
Register-based retrospective cohort study from Finland.


METHODS
National Medical Birth Register data during 2006-2008.


METHODS
A total of 171 731 women having singleton deliveries, of whom 3394 (1.98%) received blood transfusion.


METHODS
We calculated odds ratios (ORs) with 95% confidence intervals (CIs) by multivariate logistic regression to adjust for confounders related to maternal background and mode of delivery.


METHODS
Blood transfusion rates by risk factors.


RESULTS
Blood transfusion rate during labor increased slightly, from 1.83% in 2006 to 2.27% in 2008 (p < 0.001), during the study period. The highest rate, almost 4%, was reported in central hospitals. Advanced maternal age and primiparity predisposed to blood transfusion. A previous cesarean section increased these rates also in subsequent vaginal delivery (2.64%) compared with women who had vaginal deliveries only (0.86%, OR 3.14, 95% CI 2.65-3.72). Induction of labor almost doubled the risk for blood transfusion (adjusted OR 1.74, 95% CI 1.60-1.89). All instrumental vaginal deliveries (adjusted OR 2.46, 95% CI 2.25-2.69) and any cesarean sections (adjusted OR 1.80, 95% CI 1.66-1.96) increased this risk. Delivery of a large-for-gestational age newborn increased the blood transfusion risk over twofold.


CONCLUSIONS
As previous cesarean section includes an increased risk for blood transfusion, even in subsequent deliveries, it is essential to consider the mode of labor carefully. The blood transfusion rate was the highest in central hospitals, suggesting differences in blood transfusion practice.
Department of Obstetrics and Gynecology, University Hospital, Helsinki, Finland. maija.jakobsson@fimnet.fi
Maija
M
Jakobsson
Mika
M
Gissler
Anna-Maija
AM
Tapper
D000328:Adult; D001803:Blood Transfusion / Q000706:statistics & numerical data*; D002585:Cesarean Section / Q000706:statistics & numerical data; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000706:statistics & numerical data*; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D018743:Perinatal Care / Q000706:statistics & numerical data*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D014592:Uterine Hemorrhage / Q000453:epidemiology; D016387:Women's Health; D055815:Young Adult