Pregnant women who later got preeclampsia had more of several specific bacteria types (Methanosaeta, Desulfomicrobium, Enterococcus, Mycobacterium, Thiobacillus, and Ochrobactrum) in their mouths compared to women who stayed healthy.

The types and amounts of bacteria in the mouths of pregnant women who later got preeclampsia were more varied between individuals compared to women who stayed healthy.

Pregnant women who later got preeclampsia had less of a specific bacteria called Veillonella parvula in their mouths compared to women who stayed healthy during pregnancy.