After comparing the fundus appearance of pregnant women in their third trimester using optical coherence tomography, researchers in Brazil have hypothesized that preeclampsia can cause a choroidal thickening that begins in the peripapillary area.

The cross-sectional study measured 27 healthy pregnant women and 47 age-matched pregnant women with the condition. In the preeclampsia group, researchers classified 26 as having mild cases and 21 as having severe. Women with severe preeclampsia tended to have thicker choroids in comparison with mild preeclamptic and healthy pregnant women.

The choroid was also significantly thicker at all points analyzed in preeclamptic patients with serous retinal detachment in comparison with preeclamptic patients without the condition. When comparing the healthy group and the group with preeclampsia, the choroidal thickness was statistical significant only in nasal measures. Researchers are led to believe that, as the imbalance increases, the entire choroid becomes thickened.