INTRAPARTUM FETAL BLOOD SAMPLING

1
INTRAPARTUM FETAL BLOOD SAMPLING HOW MUCH IS
ENOUGH? Santangeli L, Ratnavelu N, Hair WM,
Thomson AJ Department of Obstetrics
Gynaecology,NHS Greater Glasgow Clyde,
Scotland
Introduction Intrapartum fetal blood sampling
(FBS) is a crucial tool in the assessment of
fetal wellbeing. National guidelines exist
providing guidance on how to interpret FBS
results and what action is appropriate (NICE
Guidance, 2007). No published guidance or
evidence exists regarding the number of samples
required to support clinical decision-making we
sought to address this in the current study.
Key results 10/50 women had an FBS pH lt7.25. In
those patients whose first FBS pH was lt7.20
(n6), all subsequent samples were also
abnormal. In patients whose first pH was
7.207.25 (n4), subsequent pHs varied (range
7.20-7.29), but clinical decisions were based on
the initial result.
FBS sampling times ranged from 6-45 minutes. In 6
patients, the sampling times took more than 35
minutes.
Methods FBS were obtained from 50 labouring
women. Other data gathered included number of
samples obtained and analysed, sampling time, pH
values and subsequent clinical decisions. An
abnormal FBS value necessitating delivery or
re-sampling was defined as lt7.25.

• Conclusions
• In those patients where FBS is indicated,
  there appears to be no benefit in obtaining more
  than one result
• Multiple samples may lead to unnecessary delays
  in clinical decision-making
• Consideration should be given to standardising
  practice amongst practitioners in labour ward

Results 160 samples were obtained (median per
patient 3, range 0-6), and 71 were processed
successfully (the remainder were reported as
air, gas in sample, insufficient).