Determination of pH or lactate in fetal scalp blood in management of intrapartum fetal distress: randomised controlled multicentre trial

Wiberg-Itzel, E consultant obstetrician
Lipponer, C consultant obstetrician
Norman, M consultant obstetrician
Herbst, A consultant obstetrician
Prebensen, D consultant obstetrician
Hansson, A consultant obstetrician
Bryngelsson, A-L consultant obstetrician
Christoffersson, M consultant obstetrician
Sennström, M senior registrar
Wennerholm, U-B consultant obstetrician
Nordström, L consultant obstetrician and head of department

¹ Departments of Obstetrics and Gynaecology Söder Hospital, Stockholm
² Sahlgrenska University Hospital, East, Gothenburg
³ Danderyd Hospital, Stockholm
⁴ Lund University Hospital, Lund
⁵Trollhättan Central Hospital, Trollhättan
⁶ Karlstad Central Hospital, Karlstad
⁷ Örebro University Hospital, Örebro
⁸Kalmar County Hospital, Kalmar
⁹ Karolinska University Hospital, Karolinska Institute, 171 76 Stockholm, Sweden

Correspondence to: L Nordström [email protected]

We thank all the women who took part in the trial and the obstetricians and midwives who recruited patients and managed their labours. The following hospitals took part: Danderyd, Kalmar, Karlstad, Karolinska, Lund, Söder Hospital, Trollhättan, Örebro, Gothenburg, Linköping. We also thank Hans Pettersson, Department of Biostatistics, Karolinska Institute at Söder Hospital, Stockholm, Sweden, for excellent statistical advice. The independent steering committee comprised Sven Cnattingius, Bengt Persson, Magnus Westgren, Karolinska Institutet, Stockholm, Sweden.

Contributors: LN had the original idea for the study, launched the network of collaborators, contributed to study design, the creation of a web based randomisation and reporting database, analysis and interpretation of data, and writing the paper and is guarantor. EW-I contributed to the study design, implemented the guidelines to all departments, contributed to analysis and interpretation of the data and writing the paper. CL, MN, AHe, DP, AHa, A-LB, MC, MS, and U-BW contributed to the study design, analysis and interpretation of data, and writing the paper. All authors have seen and approved the final version.

Funding: Signhild Engqvists Stiftelse, Allmänna BB’s Minnesfond, the regional city council research and development foundations, the health and medical committee of the region Västra Götaland, and Medexa, Lomma, Sweden.

Competing interests: EW-I and LN are shareholders in Obstecare, a company dealing with development of IT based decision support for labour dystocia. No product is yet on the market.

Ethical approval: Karolinska Institutet, Stockholm, Sweden (file record 109/02).

Provenance and peer review: Not commissioned; externally peer reviewed.

Accepted: 31 March 2008

doi:10.1136/bmj.39553.406991.25

BMJ 336(7656):p 1284-1290, June 7, 2008.

Objective

To examine the effectiveness of pH analysis of fetal scalp blood compared with lactate analysis in identifying hypoxia in labour to prevent acidaemia at birth.

Design

Randomised controlled multicentre trial.

Setting

Labour wards.

Participants

Women with a singleton pregnancy, cephalic presentation, gestational age ≥34 weeks, and clinical indication for fetal scalp blood sampling.

Interventions

Standard pH analysis (n=1496) or lactate analysis (n=1496) with an electrochemical microvolume (5 μl) test strip device. The cut-off levels for intervention were pH <7.21 and lactate >4.8 mmol/l, respectively.

Main outcome measure

Metabolic acidaemia (pH <7.05 and base deficit >12 mmol/l) or pH <7.00 in cord artery blood.

Results

Metabolic acidaemia occurred in 3.2% in the lactate group and in 3.6% in the pH group(relative risk 0.91, 95% confidence interval 0.61 to 1.36). pH <7.00 occurred in 1.5% in the lactate group and in 1.8% in the pH group (0.84, 0.47 to 1.50). There was no significant difference in Apgar scores <7 at 5 minutes (1.15, 0.76 to 1.75) or operative deliveries for fetal distress (1.02, 0.93 to 1.11).

Conclusion

There were no significant differences in rate of acidaemia at birth after use of lactate analysis or pH analysis of fetal scalp blood samples to determine hypoxia during labour.

Trial registry

ISRCT No 1606064.