This is going to be a long one, readers, so sit tight!
The American College of Obstetricians and Gynecologists (ACOG) has issued a new practice bulletin on continuous electronic fetal monitoring in labor. Given how thoroughly this practice has been embraced by obstetricians – it was used in more than 85% of births in 2002, up from 45% in 1980 – some readers may be surprised by the bulletin’s strong statements about potential harms of and lack of evidence supporting its use.
Continuous electronic fetal monitoring (cEFM) was introduced in the early 1970s in the hopes of reducing certain complications such as cerebral palsy or fetal death, which were believed to occur because the fetus wasn’t getting enough oxygen. However, these expected benefits were not demonstrated prior to cEFM becoming nearly ubiquitous in obstetrics. As a New York Times piece on the bulletin points out: “Continuous monitoring became a standard obstetrical procedure before studies could show if the benefits outweighed the risks, and without clear-cut guidelines on how doctors should interpret the findings.”
The authors of the ACOG bulletin explain that – in weighing the evidence now – the efficacy of cEFM should be “judged by its ability to decrease complications, such as neonatal seizures, cerebral palsy, or intrapartum fetal death, while minimizing the need for unnecessary obstetric interventions, such as operative vaginal delivery or cesarean delivery.” [emphasis added]
Because there are no randomized trials comparing cEFM with other monitoring methods, the benefits “are gauged from reports comparing it with intermittent auscultation” [periodic listening via stethoscope].
The report states that cEFM does not reduce the risk of perinatal mortality or of cerebral palsy. It is thought to reduce the risk of neonatal seizures by about 50%; these seizures are estimated to occur in about 1 in 500 neonates, with a good prognosis for most patients. On the risk side, the authors very clearly note that cEFM increases the risk of c-section, and the risk of vacuum and forceps operative delivery.
Given these findings – though with a caveat that current practices for frequency of monitoring may make it logistically difficult under some current models of labor management and hospital staffing – the bulletin states:
Given that the available data do not show a clear benefit for the use of EFM over intermittent auscultation, either option is acceptable in a patient without complications.
The old practice bulletin has already been withdrawn, so it’s difficult to compare exact changes, but an ACOG press release explains that “One notable update in the guidelines is the three-tier classification system for FHR tracings (print-outs of the fetal heart rate).” The authors defined three categories of tracings with specific clinical criteria for each; they are normal (no action required), indeterminate (further evaluation and surveillance needed), and abnormal (requiring prompt evaluation).
Interestingly, the guideline does not recommend immediate cesarean section for the Category III tracings. Instead, it indicates that initial evaluation and treatment may include discontinuation of labor stimulating drugs, cervical exam to check for things like umbilical cord prolapse, changing the woman’s position, monitoring her blood pressure, and assessment of uterine contractions. They further explain that “If a Category III tracing does not resolve with these measures, delivery should be undertaken.”
The authors also explain that “Our goal with the ACOG guidelines was to define existing terminology and narrow definitions and categories so that everyone is on the same page.” This may be necessary in part because providers may often interpret fetal monitor strips very differently from one another, as evidenced here:
For example, when four obstetricians examined 50 cardiotocograms, they agreed in only 22% of the cases. Two months later, during the second review of the same 50 tracings, the clinicians interpreted 21% of the tracings differently than they did during the first evaluation. In another study, five obstetricians independently interpreted 150 cardiotocograms. The obstetricians interpreted the tracings similarly in 29% of the cases, suggesting poor interobserver reliability.
Continuous fetal monitoring may have become commonly used in part because clinicians hoped to avoid malpractice judgments. If there is little agreement between clinicians looking at these tracings, and little evidence of fetal benefit, however, that rationale may need to be discarded. The NY Times piece points out that “Monitoring results are widely used by lawyers to bolster malpractice cases of spurious merit” – in other words, a technique that clinicians have widely adopted with the hope that it would protect them and their patients may instead have a negative effect on their careers, finances, and (last but not least) patients.
Overall, the practice bulletin agrees pretty well with what advocates (including OBOS) have been saying for some time, by addressing reducing women’s exposure to unnecessary procedures, clearly outlining the risks and lack of many assumed benefits of continuous EFM, suggesting that the high tech option isn’t always better, acknowledging that providers may err and vary, and providing the possibility of initial measures that don’t involve going straight to c-section. It’s too early to tell what the response to this ACOG bulletin might be (and further refinements are expected next year), but we’ll certainly keep an eye out for commentary – please leave yours in the comments.