Comparing second-line tests to assess fetal wellbeing in Labor: a feasibility study and pilot randomized controlled trial

Abstract

Objective

To explore the feasibility of conducting a randomized controlled trial (RCT) designed to compare the performance of digital fetal scalp stimulation (dFSS) and fetal blood sampling (FBS) as second-line tests of fetal wellbeing in Labor.

Design

A feasibility study included 66 women who consented to both dFSS and FBS performed contemporaneously. A pilot randomized controlled trial included 50 women who were randomized to either dFSS or FBS.

Setting

University-affiliated maternity hospital.

Population

Women in Labor who required second-line testing of fetal well-being following abnormal fetal heart rate monitoring.

Outcome measures

The primary outcome of interest was delivery by emergency cesarean section. Secondary outcomes included maternal and perinatal morbidity outcomes and procedural factors.

Results

Of the 66 women recruited to the feasibility study 50 (76%) received the two interventions as per protocol. The demographic data indicated that future RCT should be limited to nulliparous women. After initial training and reminders, the dFSS procedure appeared to be acceptable to patients and clinicians and was interpreted appropriately. Recruitment of eligible women to the pilot RCT was successful (88%) with 50 of 63 eligible women randomized (79%) and no drop-outs. The cesarean section rate was high in both arms as expected with a cohort of women requiring second-line tests for abnormal fetal heart rate monitoring in Labor (5/25; 20% dFSS versus 13/25; 52% FBS, p = .018). Conservative estimates suggest that a sample size of 2500 randomized women would be required for a definitive RCT.

Conclusions

This study suggests that dFSS, which has the potential to be a reliable alternative to FBS, could be evaluated in a well-designed randomized controlled trial.

Trial registration

The definitive trial has been registered ISRCTN 13295826.

Keywords:

• Cesarean section
• digital fetal scalp stimulation (dFSS)
• feasibility
• fetal blood sampling (FBS)
• Labor
• pilot study

Details of ethics approval

Coombe Women & Infants University Hospital REC April 2017.

Contribution to authorship

DJM had the original idea for the study which was designed by both authors. OH recruited the patients and collected the data. The analysis and drafting of the manuscript was completed by both OH and DJM.

Acknowledgements

We would like to acknowledge the women who participated in the study and provided important insights on the conduct and design of the study, and the health professionals caring for them.

Disclosure statement

No potential conflict of interest was reported by the authors.