The uteroplacental circulation in the placenta can have a major impact on the fetus. Near infrared spectroscopy (NIRS) is the noninvasive method of measuring changes in blood volumes and oxygen concentrations in living tissue. The purpose of this study is to monitor changes in placental tissue oxygen index (TOI) levels, in patients with intrauterine fetal growth restriction during pregnancy, using NIRS. We measured placental TOI values of 15 normal pregnant woman and 15 patients with intrauterine growth restriction admitted to our hospital. The placenta was assessed by ultrasound examination and NIRS was performed on all patients. The TOI values of the IUGR group when hospitalized was 78.6 +/- 1.6 (SD). This value was significantly higher than that of the controls (78.6 +/- 1.6 [SD] versus 70.2 +/- 0.4 [SD]). And the TOI values of the IUGR group, when measured before delivery, were 77.8 +/- 1.6 (SD). The TOI values of the IUGR group before delivery were significantly higher than those of the control group (77.8 +/- 1.6 [SD] versus 70.3 +/- 0.4 [SD]). We propose that NIRS is a candidate, noninvasive method for assessing placental oxygen dynamics on a real-time basis. In the near future it may contribute to perinatal medical practice.
Near-infrared spectroscopy (NIRS) has been used as a noninvasive method for monitoring the real-time oxygenation status in areas such as the brain and striated muscle. Because the oxygenation status of the placenta is closely related to the fetal condition, monitoring placental oxygenation through the maternal abdomen is desirable. We performed transabdominal monitoring of oxygenation of the placenta by NIRS in 11 women. We improved the conventional probe of the NIRO 300 system (Hamamatsu Photonics KK, Hamamatsu, Japan) to obtain placental oxygenation data. With this probe, we succeeded in obtaining oxyhemoglobin and deoxyhemoglobin data through the maternal abdomen. We believe NIRS will prove to be useful for intrapartum monitoring.
We evaluated the clinical usefulness of near-infrared spectroscopic quantitative measurement of placental oxygenation for the noninvasive estimation of uteroplacental function in pregnant women. We performed a prospective, observational clinical study. Women without complications (N = 15), women with threatened preterm delivery (TPD; N = 6), and women with intrauterine fetal growth restriction (IUGR; N = 6) were enrolled. Measurements of placental tissue oxygenation index (TOI) using the NIRO-300 (Hamamatsu Photonics, Hamamatsu City, Japan) were recorded. Mean TOI was 72.3 +/- 5.3% in women without complications, 72.9 +/- 5.6% in pregnant women with TPD, and 78.7 +/- 3.0% in pregnant women with IUGR. Mean TOI in pregnant women with IUGR was significantly higher than that of the other two groups (P < 0.05). In the IUGR group, although gestational age at measurement on admission was less than that made during hospitalization (P < 0.05), there were no differences in the TOI in relation to gestational age at measurement. Higher TOIs in pregnant women suggest decreased placental function. Monitoring the TOI by near-infrared spectroscopic quantitative measurement may have a high potential for clinical application, particularly in prenatal management.
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.
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