Fetal growth restriction, placental ischemic lesions and near-infrared spectroscopy evaluation of maternal tissue oxygenation in preeclampsia (the FINE study): a prospective observational study.

BACKGROUND: Maternal peripheral tissue oxygenation may vary with fetal and placental involvement in preeclampsia. We explored associations between thenar near-infrared spectroscopy parameters, fetal growth restriction and placental ischemic lesions. METHODS: This single-center prospective observational study included 61 women with preeclampsia. Baseline tissue oxygen saturation, desaturation slope, resaturation slope and hyperemic area under the curve were measured during a three-minute vascular occlusion test. Logistic models were adjusted for preeclampsia with severe features. Post hoc sensitivity analyses additionally adjusted for gestational age at assessment. RESULTS: Thirty-three women had fetal growth restriction and 39 had placental ischemic lesions. Baseline tissue oxygen saturation was higher with fetal growth restriction (adjusted odds ratio 1.16, 95% confidence interval 1.03-1.32; P = 0.02) and placental ischemic lesions (adjusted odds ratio 1.17, 95% confidence interval 1.03-1.34; P = 0.02). After additional adjustment for gestational age, neither association remained statistically significant (fetal growth restriction: adjusted odds ratio 1.07, 95% confidence interval 0.93-1.22; P = 0.37; placental ischemic lesions: adjusted odds ratio 1.10, 95% confidence interval 0.94-1.29; P = 0.23). No statistically significant between-group differences were detected in the selected vascular occlusion test-derived parameters. DISCUSSION: Baseline thenar tissue oxygen saturation showed associations with fetal growth restriction and placental ischemic lesions, whereas selected vascular occlusion test responses did not differ between groups. The attenuation of these associations after adjustment for gestational age highlights the importance of measurement timing and provides a basis for longitudinal studies of maternal peripheral tissue oxygenation in preeclampsia.