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

https://doi.org/10.1016/0002-9378(94)90081-7Get rights and content

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 (≤ 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 (≤ 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.

Cited by (138)

  • Intraoperative management of the neonate

    2022, Goldsmith's Assisted Ventilation of the Neonate: An Evidence-Based Approach to Newborn Respiratory Care, Seventh Edition
  • Gestational age impacts birth to placental weight ratio and umbilical cord oxygen values with implications for the fetal oxygen margin of safety

    2022, Early Human Development
    Citation Excerpt :

    Moreover, retrospective cohort study has shown that infant mortality rates at 39, 40, and 41 weeks` gestation are lower than the overall mortality risk of expectant management for an additional week [22], which is likely to be hypoxia related [20]. Study limitations include the extent to which labor and delivery affect cord O2 findings, with pulse oximetry showing O2 saturation to be marginally decreased through labor [43], although fetal scalp sampling shows PO2 to be little changed until a marginal fall just before delivery with these values then comparable to umbilical artery values [44]. However, cord O2 findings at birth will relate to pre-labor/delivery oxygenation and can be reflective of this if the sample size is sufficient and covariates controlled for with large population-based studies showing cord O2 values to be lower in SGA infants [19,37] as similarly seen with cordocentesis prior to labor [8,10].

  • Oxygen Therapy in the Delivery Room: What Is the Right Dose?

    2018, Clinics in Perinatology
    Citation Excerpt :

    The question remains: if we start at room air, how to best titrate the oxygen to meet these 2 objectives? The fetus in labor has an oxygen saturation of around 50%, which can decrease to as low as 30% without adversely affecting the fetus.11,13,63 Multiple studies have demonstrated that a term newborn takes about 10 minutes after birth to reach an oxygen saturation of greater than 90%.14,15

  • Maternal body mass index impacts fetal-placental size at birth and umbilical cord oxygen values with implications for regulatory mechanisms

    2017, Early Human Development
    Citation Excerpt :

    Study limitations include the categorization of SGAs using birth weights < 10th percentile since some of these infants will be constitutionally small rather than growth restricted, although this classification is widely used for denoting FGR infants. Additionally, labor and delivery are likely to affect fetal oxygenation with pulse oximetry showing oxygen saturation to be marginally decreased through labor [35], although fetal scalp sampling shows PO2 to be little changed until a marginal fall just before delivery with these values then comparable to umbilical artery values [36]. However, umbilical cord PO2 obtained post-delivery must also relate to pre-labor/delivery oxygenation and can be reflective of this if the sample size is sufficient since large population studies show cord oxygen values to be lower with advancing gestation [37] and in FGR infants [16] as similarly seen with cordocentesis prior to labor [38].

View all citing articles on Scopus

Supported by Nellcor, Inc., Hayward, California.

View full text