Elevated second-trimester maternal serum hCG: a marker of inadequate angiogenesis.

OBJECTIVE: To measure angiogenin, a potent inducer of neovascularization and interleukin-6, as an indicator of acute inflammation, in second-trimester amniotic fluid of patients with elevated maternal serum hCG. METHODS: In this case-control study, 20 patients with elevated maternal serum hCG (at least 2.0 multiples of median) at triple screen were matched 2:1 with controls on the basis of year of amniocentesis, parity, and race. Inclusion criteria were 1) singleton gestation, 2) no evidence of anomalies, and 3) genetic amniocentesis. Amniotic fluid was immunoassayed for angiogenin and interleukin-6. The immunoassay sensitivity for angiogenin was 0.026 ng/mL, interassay coefficient of variation 4.6%, and intra-assay coefficient of variation 2.9%. For interleukin-6, the immunoassay sensitivity was 2.37 pg/mL, interassay coefficient of variation 2.7%, and intra-assay coefficient of variation 1.9%. Angiogenin and interleukin-6 values were normalized by using natural log transformation for statistical analysis. Statistical analysis included analysis of variance and stepwise regression, with P < .05 significant. RESULTS: After correcting (by multivariate regression) for gestational age at sampling and nulliparity, amniotic fluid angiogenin levels were significantly lower in the study subjects than in controls (26%+/-11% lower, P=.004), whereas the interleukin-6 levels did not change significantly (34%+/-40% lower, P=.3). CONCLUSION: Amniotic fluid angiogenin levels are significantly lower in patients with elevated maternal serum hCG at triple screen, suggesting inadequate angiogenesis, but interleukin-6 values do not differ significantly.

Intrapartum fetal pulse oximetry: past, present, and future.

Oxygen saturation monitoring (pulse oximetry) has markedly improved medical care in many fields, including anesthesiology, critical care, and newborn intensive care. In obstetrics, fetal heart rate monitoring remains the standard for intrapartum assessment of fetal well-being. Fetal heart rate monitoring is sensitive but nonspecific for detecting fetal compromise. Additional clinical information is needed to discern those fetuses not at risk for development of intrapartum acidosis to avoid unnecessary intervention. Fetal oxygen saturation monitoring is a new technique currently under development. This article reviews the evolution of intrapartum fetal oxygen saturation monitoring and proposes directions for future investigation.

Intrapartum fetal pulse oximetry: the effects of maternal hyperoxia on fetal arterial oxygen saturation.

OBJECTIVE: Our purpose was to observe the effects of maternal oxygen administration on fetal arterial oxygen saturation in normal human fetuses during labor. STUDY DESIGN: Twenty healthy women with uncomplicated pregnancies were studied during active labor at term. Arterial oxygen saturation was measured by a noninvasive reflectance pulse oximeter designed for fetal application (Nellcor, Inc, Pleasanton, Calif.). The first group was studied during 20-minute intervals of inspired oxygen concentrations of 21%, 40%, and 100%. In a second group the effects of prolonged (45 minutes) supplemented 40% oxygen administration were evaluated. Differences between groups were analyzed by analysis of variance; significance was considered at p < 0.05. RESULTS: A significant increase in fetal arterial oxygen saturation (50% +/- 8% vs 64% +/- 6%, p < 0.0001) was detected in the group given 100% oxygen for 20 minutes but not in the groups that received 40% oxygen for 20 or 45 minutes. CONCLUSIONS: Prolonged maternal administration of 40% oxygen resulted in no significant demonstrable change in fetal arterial oxygen saturation determined by reflectance pulse oximetry in normal fetuses. Because the administration of oxygen by standard mask techniques rarely results in 40% inspired oxygen concentration, fetal benefits of such intrapartum maternal oxygen administration are questionable.

Intrapartum fetal pulse oximetry: fetal oxygen saturation trends during labor and relation to delivery outcome.

OBJECTIVES: Our purpose was to study fetal arterial oxygen saturation trends by continuous pulse oximetry during labor in subjects with normal and abnormal delivery outcomes. STUDY DESIGN: Continuous fetal arterial oxygen saturation was measured during labor with a noninvasive reflectance pulse oximeter designed for fetal application. Averaged arterial oxygen saturation values were compared between stage 1 and stage 2 of labor, with stage 1 further subdivided into early (< or = 4 cm), middle (5 to 7 cm), and late (8 to 10 cm) phases. Delivery outcome was considered to be abnormal for any of the following conditions: gestational age < 37 weeks, maternal oxygen administration, delivery by cesarean section, 5-minute Apgar score < 7, umbilical artery pH < 7.10, birth weight < 2500 gm, or newborn intensive care unit admission. RESULTS: A total of 291 subjects were studied: 142 in Provo, 90 in Nijmegen and 59 in San Francisco. Subjects with delivery complications (n = 125) were evaluated separately from those with normal delivery outcomes (n = 160). Fetal arterial oxygen saturation was 58% +/- 10% (mean +/- SD) during the cumulative period of study for the normal-outcome group. A significant decrease (paired t test, p < 0.001) in fetal arterial oxygen saturation occurred from stage 1 (59% +/- 10%) to stage 2 (53% +/- 10%) labor. When stage 1 was subdivided into early (< or = 4 cm), middle (5 to 7 cm), and late (8 to 10 cm) phases, a gradual decreasing trend in fetal arterial oxygen saturation was observed: 62% +/- 9%, 60% +/- 11%, and 58% +/- 10%. CONCLUSIONS: With the use of reflectance pulse oximetry, a statistically significant decrease in fetal arterial oxygen saturation was observed during labor in women with normal and abnormal delivery outcomes.

Intrapartum fetal pulse oximetry in the presence of fetal cardiac arrhythmia.

We report our experience with a reflectance pulse oximeter in intrapartum monitoring of a fetus with atrial flutter and heart block. During labor fetal arterial oxygen saturation ranged between 50% and 85%. Spontaneous vaginal delivery occurred with good maternal and neonatal outcome.

Preliminary experience with intrapartum fetal pulse oximetry in humans.

Electronic fetal heart rate (FHR) monitoring is commonly used to assess fetal well-being during labor. Nonreassuring patterns in many cases are associated with normal fetal acid-base condition, leading to unnecessary operative intervention. Fetal pulse oximetry has several potential advantages over FHR monitoring because it assesses not only pulse, but also arterial oxygen saturation and tissue perfusion. We describe our preliminary experience with the Nellcor N-400 Fetal Oxygen Saturation Monitor and FS-10 Oxisensor in 73 subjects during active labor at term. The mean (+/- standard deviation) duration of monitoring was 161.4 +/- 106.0 minutes, with sensor contact achieved 67.3 +/- 22.5% of the time during labor. Data were successfully recorded in all patients, with a reliable signal obtained 50.1 +/- 21.6% of the time during labor. The mean fetal oxygen saturation was 57.9 +/- 10.0%. The potential for research and clinical applications appears promising with further sensor and monitor development.