From the Guidelines
Intrapartum fetal monitoring should be employed in a low-risk patient, with reconsideration as labor progresses, and interventions such as position changes, maternal oxygenation, and intravenous fluid administration may be used if the FHR tracing is abnormal. When considering the management of intrapartum fetal monitoring, it is essential to prioritize techniques that can accurately assess fetal well-being and promptly identify potential complications. According to a study published in the American Family Physician in 2009 1, continuous EFM tracing is a crucial tool in this context. Some key points to consider in intrapartum fetal monitoring include:
- The use of fetal scalp pH sampling or fetal stimulation when continuous EFM tracing is indeterminate to assess for the possible presence of fetal acidemia
- The replacement of fetal scalp pH testing with fetal stimulation or immediate delivery in the United States
- The importance of identifying absent or minimal variability without spontaneous accelerations, as the presence of an acceleration after scalp stimulation or fetal acoustic stimulation indicates that the fetal pH is at least 7.20, as shown in a meta-analysis 1. In clinical practice, the goal of intrapartum fetal monitoring is to ensure the best possible outcomes for both the mother and the fetus, minimizing morbidity, mortality, and optimizing quality of life.
From the Research
Fetal Scalp Blood Sampling (FSBS)
- FSBS is a method of fetal surveillance that may avoid cesarean delivery of the healthy fetus or indicate the need for immediate delivery of a compromised fetus 2
- The efficacy of FSBS has been questioned by some researchers, with studies showing ambiguous results on its ability to decrease the rate of operative delivery for fetal distress 3
Physiological Basis and Scientific Evidence
- Fetal cardiotocography has low specificity, leading to the recommendation of FSBS in cases of non-reassuring cardiotocography 3
- The fetal scalp is supplied by vessels outside the skull, which may be compressed during contractions, bringing into question the representativeness of the scalp capillary bed for central circulation 3
- A review of published literature and randomized controlled trials suggests that FSBS can reduce the risk of operative delivery and provide additional information on fetal wellbeing 4
Clinical Guidelines and Recommendations
- The Society of Obstetricians and Gynaecologists of Canada recommends the use of FSBS as a complementary tool to improve the specificity and sensitivity of electronic cardiotocography 5
- A recent study confirms the validity and reliability of current guideline thresholds for fetal scalp pH in category II fetal heart rate, with pH drop rates accelerating at thresholds of 7.25 and 7.20 6
Uses and Limitations of FSBS
- FSBS can be used to assess fetal well-being during labor and provide additional information on fetal reserves before decisions are made concerning operative delivery 2, 4
- However, the scientific agreement on the evidence for using FSBS to decrease the rate of operative delivery for fetal distress is ambiguous, and more research is needed to fully understand its benefits and limitations 3