|Source||Location and Type of Study||Intervention||Stillbirths/Perinatal Outcomes|
|Reviews and meta-analyses|
|East et al. 2007 ||
USA, Australia, Germany.|
Meta-analysis (Cochrane). 4 RCTs included (N = 1789).
|To compare the effectiveness and safety of fetal pulse oximetry + cardiotocography (intervention) vs. conventional surveillance techniques (cardiotocography only).||
Fetal death (miscarriage+SB)/NMR: RR = 0.93 (95% CI: 0.20–4.44) [NS].|
[3/942 vs. 3/847 in intervention and control groups, respectively] for gestation from 36 weeks and fetal blood sampling (FBS) not required prior to study entry.
|Neilson 2006 ||
Sweden, Finland, UK, Hong Kong, Netherlands, Singapore.|
Meta-analysis (Cochrane). 4 RCTs included (N = 9829).
|To compare the effects of analysis of fetal ECG waveforms during labour (intervention) vs. alternative methods of fetal monitoring (no ECG) (controls).||
PMR: RR = 2.29 (95% CI: 0.59–8.83) [NS].|
[6/4953 vs. 2/4876 in intervention and control groups, respectively].
|Alfirevic et al. 2006 ||
Athens, Copenhagen, Denver, Dublin, Australia, Pakistan, USA, Sheffield.|
Meta-analysis (Cochrane) 11 RCTs included (N = 33,513).
|To assess the effectiveness of continuous cardiotocography during labour (intervention) vs. intermittent auscultation (controls).||
PMR: RR = 0.85 (95% CI: 0.59–1.23) [NS].|
[50/16849 vs. 57/16664 in intervention and control groups, respectively].
|Seelbach Gobel 1999 ||
Germany. Multicentred study involving 3 obstetric centres.|
Observational study. N = 400 deliveries monitored by fetal pulse oximetry.
|Compared the durations of different fetal arterial oxygen saturations in neonates with a pH < 7.15 vs. ≥ 7.15, base excess < -12 mmol/L vs. > -12 mmol/L in the umbilical artery post partum and in neonates with an Apgar score < 7 vs. ≥ 7.||
Duration of low fetal arterial oxygen saturation: significantly longer in neonates with a 1-minute Apgar score <7 vs. ≥ 7, with pH < 7.15 vs. = 7.15 and with base excess < -12 mmol/L vs. ≥ -12 mmol/L.|
Duration of medium fetal arterial oxygen saturation: no significant differences between the groups.
Duration of high fetal arterial oxygen saturation: significantly shorter for children with pH < 7.15 vs. ≥ 7.15 and with base excess < -12 mmol/L vs. ≥ -12 mmol/L; no significant difference in children with Apgar score < 7 vs. ≥ 7.
The duration of low fetal arterial oxygen saturation proved to be the best predictor of a decline of scalp pH between 2 fetal scalp blood samples. The pH declined significantly with a longer duration of low fetal arterial oxygen saturation (0.02 per 10 minutes). No decrease of pH by more than 0.05 was observed unless fetal arterial oxygen saturation had remained at ≤ 30% for ≥ 10 minutes.
|Stiller et al. 2002 ||
Test sensitivity and specificity analysis. N = 107 sets of measures.
|To determine the sensitivity and specificity for acidosis of intrapartum fetal oxygen saturation measured by reflectance pulse oximetry.||
Mean fetal oxygen saturation was 42.8%, over the mean 132 minutes of 107 recordings.|
Depending on stage and umbilical artery parameter, fetal oxygen saturation cutoffs were 33% to 36%, with sensitivities of 0.67 to 0.8 and specificities of 0.62 to 0.90.
Umbilical artery values tended to be less favorable at SpO2 levels < 40%; above 40% no unfavorable values were reported.