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Fetal pulse oximetry for fetal assessment in labour

  • Review
  • Intervention

Authors

  • Christine E East,

    Corresponding author
    1. Monash University/Southern Health, School of Nursing and Midwifery/Maternity Services, Clayton, Victoria, Australia
    • Christine E East, School of Nursing and Midwifery/Maternity Services, Monash University/Southern Health, 246 Clayton Road, Clayton, Victoria, 3168, Australia. christine.east@monash.edu.

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  • Lisa Begg,

    1. Royal Women's Hospital, Maternal Fetal Medicine, Department of Obstetrics, Parkville, Victoria, Australia
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  • Paul B Colditz

    1. The University of Queensland, Royal Brisbane & Women's Hospital, Perinatal Research Centre, Herston, Queensland, Australia
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Abstract

Background

Pulse oximetry could contribute to the evaluation of fetal well-being during labour.

Objectives

To compare the effectiveness and safety of fetal pulse oximetry with conventional surveillance techniques.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2010), MEDLINE (1994 to May 2010), EMBASE (1994 to May 2010), Current Contents (1994 to May 2010) and contacted experts in the field.

Selection criteria

All published and unpublished randomised controlled trials that compared maternal and fetal outcomes when fetal pulse oximetry was used in labour, with or without concurrent use of conventional fetal surveillance, compared with using cardiotocography (CTG) alone.

Data collection and analysis

At least two independent authors performed data extraction. We performed analyses on an intention-to-treat basis. We sought additional information from the investigators of three of the reported trials.

Main results

We included six published trials comparing fetal pulse oximetry and CTG with CTG alone (or when fetal pulse oximetry values were blinded). The published trials, with some unpublished data, reported on a total of 7654 pregnancies. Differing entry criteria necessitated separate analyses, rather than meta-analysis of all trials.

Systematic review of four trials from 34 weeks not requiring fetal blood sampling prior to study entry showed no significant differences in the overall caesarean section rate between those monitored with fetal oximetry and those not monitored with fetal pulse oximetry or for whom the fetal pulse oximetry results were masked (risk ratio (RR) 0.99, 95% confidence intervals (CI) 0.86 to 1.13, n = 4008). Neonatal seizures and neonatal encephalopathy were rare. No studies reported details of assessment of long-term disability.

There was a statistically significant decrease in caesarean section for nonreassuring fetal status in the fetal pulse oximetry plus CTG group compared to the CTG group, gestation from 34 weeks (RR 0.65, 95% CI 0.46 to 0.90). There was no statistically significant difference in caesarean section for dystocia when fetal pulse oximetry was added to CTG monitoring, compared with CTG monitoring alone, although the incidence rates varied between the trials.

Authors' conclusions

The data provide limited support for the use of fetal pulse oximetry when used in the presence of a nonreassuring CTG, to reduce caesarean section for nonreassuring fetal status. The addition of fetal pulse oximetry does not reduce overall caesarean section rates. A better method to evaluate fetal well-being in labour is required.

Plain language summary

Fetal pulse oximetry for fetal assessment in labour

Using fetal pulse oximetry to assess the baby's well-being during labour does not change overall caesarean section rates.

During labour, the well-being of the baby can be assessed intermittently using a Pinard stethoscope or hand held monitor, or continuously using cardiotocography (CTG, sometimes called electronic fetal monitoring, EFM) or assessing the baby's condition with an electrocardiogram (ECG). There are also additional tests that can be used if the baby is thought to be getting short of oxygen, like testing the baby's blood in a sample taken from the baby's head or bottom. A new method, fetal pulse oximetry, measures how much oxygen the baby's blood is carrying. It uses a probe that sits inside the vagina during labour. The probe is said not to inhibit the woman's mobility during labour. This review looked at fetal pulse oximetry and only found trials that used it in conjunction with a CTG and compared the combined use with CTG alone. The review identified six trials involving 7654 women. Fetal pulse oximetry plus CTG showed no difference in caesarean section rates overall, nor any difference in the mother's or newborn's health, compared with CTG alone. If there was concern about the baby's well-being before the fetal pulse oximetry probe was placed, the use of fetal pulse oximetry reduced caesarean sections performed for the baby's well-being. In one of the trials, the company making the fetal pulse oximetry machines provided some funding. Further trials may be helpful.

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