Transabdominal measurement of placental oxygenation by near-infrared spectroscopy.

We evaluated the clinical usefulness of near-infrared spectroscopic quantitative measurement of placental tissue oxygenation for noninvasive estimation of uteroplacental function in pregnant women. We performed a prospective observational clinical study. Women without complications (N = 15) and women with pregnancy-induced hypertension (PIH; N = 6) were enrolled. Measurements of placental tissue oxygenation index (TOI) using NIRO-300 (Hamamatsu Photonics, Hamamatsu City, Japan) were recorded. The mean TOI in women without complications was 72.36 +/- 5.36% and 80.28 +/- 2.78% in pregnant women with PIH. The mean TOI in pregnant women with PIH was higher than that of pregnant women without complications. There were no differences in the TOI in relation to gestational age at onset of PIH, forms of PIH, or severity of hypertension. Higher TOIs in pregnant women suggest the reduced ability of the placental function. Monitoring the TOI by near-infrared spectroscopic quantitative measurement may have a high potential for clinical application, particularly in prenatal management.