Intrauterine infection may be a major cause of stillbirth in Sweden.

AIM OF THE STUDY To investigate intrauterine infection as a cause for unexplained stillbirth. METHODS Chorioamnionitis was studied in a material of stillbirths (117 subjects from the years 1985-1994) from a region in the south Sweden. Control material (126 alive and healthy newborns and with healthy mothers) was gathered from the same region. RESULTS Chorioamnionitis was a common diagnosis both with stillbirths and 'healthy' deliveries (82 and 68%, respectively). Extension of the inflammation to decidua basalis was seven times more common among stillbirths than among controls (odds ratio 7.2, confidence interval 2.8-21.9). The most common bacteria found at cultures were Escherichia coli, Coagulase negative staphylococcus, Enterococcus faecalis and group B Streptococcus. The risk for stillbirth was doubled if both inflammation and bacteria were present (odds ratio 2.3, confidence interval 0.92-5.8). Meconium discharge was more common among stillbirths than controls (odds ratio=4.7, confidence interval 1.7-14). There were no differences in any respect regarding macerated and non-macerated stillbirths. Our findings are similar to the results from studies in developing countries except for the higher incidence of stillbirths in such countries. CONCLUSIONS Thus, a large part of otherwise unexplained stillbirths might be due to ascending infections.