Reduced antioxidant capacity in second-trimester pregnancies with pathological uterine perfusion

To examine whether pathological perfusion in the second trimester is characterized by an altered plasma antioxidant capacity and to investigate whether the total antioxidant capacity in maternal plasma is related to the clinical outcome of these high-risk pregnancies.

This was a prospective cohort study that included 25 pregnancies with normal and 25 pregnancies with pathological uterine perfusion. Doppler ultrasound measurement of uterine perfusion was performed between 18 and 23 weeks of gestation. Total antioxidant capacity in maternal plasma was measured using a specific photometric assay.

Plasma antioxidant capacity of pregnant women with pathological uterine perfusion (227.3 +/- 4.0 micro mol/L) was significantly lower compared with the group with normal uterine perfusion (275.2 +/- 10.5 micro mol/L; P < 0.05). There was a significant negative correlation between antioxidant capacity and mean pulsatility index of the uterine arteries (r = -0.363; P < 0.05). Patients with pathological perfusion and a normal course of pregnancy did not show significantly changed values compared with those patients with later pre-eclampsia or intrauterine growth restriction (235.0 +/- 4.9 micro mol/L vs. 218.6 +/- 6.7 micro mol/L).

Second-trimester pregnancies with pathological uterine perfusion are characterized by a decreased antioxidant capacity in maternal plasma. This reduction is related to the impaired uteroplacental blood flow, but does not reflect the changes characteristic of the oxidative status for diseases like pre-eclampsia since the reduction of the plasma antioxidant capacity is not related to the clinical outcome of these high-risk pregnancies.