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Routine continuous electronic fetal monitoring, a.k.a., cardiotocography, during labor continues to be the norm in labor & delivery units despite being a colossal failure, and the obstetric community knows it. This is a shocking, but provable, statement. To do that, this post will:
As for where that leaves you, the “Take Away” will provide strategies on how you can work the system, including how to:
Let’s start with a look at the evidence.
What Does the Evidence Say?
The theory behind routine continuous fetal monitoring goes like this: Abnormal fetal heart rate patterns are strongly associated with stillbirth, newborn death, and neurologic injury, in particular, cerebral palsy, but while listening periodically to the fetal heart rate detects these abnormalities, intervening rarely averts these outcomes. The problem must be too little information, too late. A machine that can track the fetal heart rate and its response to contractions should enable doctors to recognize trouble sooner and rescue babies before damage is done. And by identifying distressed babies more accurately, it should also avoid unnecessary cesarean and instrumental deliveries.
The theory sounded so good that it was put into practice without testing it. By the mid-1970s, routine continuous fetal monitoring was in widespread use before ever conducting a single trial comparing its outcomes with intermittent listening.
It turned out the theory didn’t hold up. When trials were finally conducted in the 1980s and into the mid-1990s, only one, an extremely problematic Greek trial funded by a fetal monitor manufacturer, reported the benefits that were claimed for it. When data from the trials are pooled (systematic review), the evidence is clear:1 continuous fetal monitoring doesn’t reduce the incidence of death during labor or in the days after birth (perinatal mortality) or the incidence of cerebral palsy or any long-term adverse neurologic outcome. It doesn’t even reduce incidence of poor condition at birth, and it increases, not decreases, cesarean and instrumental deliveries. Continuous monitoring also interferes with mobility, increases discomfort, and pulls attention away from the laboring woman, and internal monitoring requires rupturing membranes, which has its own harms. In other words, routine continuous fetal monitoring isn’t just not beneficial, it’s harmful.
Continuous fetal monitoring has only one advantage: It reduces the number of newborns having seizures,1 but this isn’t as meaningful as it sounds. For one thing, there were no long-term ill effects. For another, newborn seizure is extremely rare—1 per 1000 newborns in low-risk women—which means the increase is miniscule. To prevent 1 newborn from having seizures, 883 low-risk women would have to undergo continuous monitoring. For a third, seizure rate depends on labor management policies. Two large trials (13,000 to 14,000 women), one in Dublin, one in Dallas, illustrate this: The Dublin trial took place in a hospital that practices “Active Management of Labor,” a policy that includes elements (routine rupture of membranes and high-dose oxytocin to augment labor) that increase stress on the baby. The Dublin trial reported a seizure rate of 4 per 1000 newborns with intermittent listening whereas the Dallas trial reported a rate of only 4 per 10,000 newborns. In Dublin, 417 women would need to be continuously monitored to prevent one seizure, but in Dallas, the number is over 3300. Finally, the increase in cesareans with continuous monitoring more than offsets any benefit in reducing seizures. Assuming a cesarean rate of 15% in low-risk women with intermittent listening, 1 excess cesarean surgery will be performed for every 6 women being continuously monitored.1
You would think continuous monitoring’s failure to reduce mortality or permanent neurologic injury would have given obstetricians pause, but it didn’t. They simply decided that the problem was execution, not the validity of the theory, and set about in the ensuing decades to try to make continuous fetal monitoring work. They came up with any number of fixes and studied them intensively, including:
The research results were consistent and unequivocal: not one of these solutions made the slightest difference.
It has been said, “When you discover that you are riding a dead horse, the best strategy is to dismount,” but obstetricians have yet to back off from routine continuous monitoring. (If you’re interested in why obstetricians continue to cling to a failed technology, scroll down to “Taking a Deeper Dive.”)
The reason continuous fetal monitoring doesn’t do what the theory says it will do and the fixes don’t change that is because the theory behind it is wrong. Let’s look at that next.
Why Doesn’t Routine Continuous Fetal Monitoring Work?
Continuous fetal monitoring doesn’t work because it can’t work. The theory behind it is based on the premise that stillbirth and newborn death and permanent neurologic disability are largely caused by insufficient oxygen in labor and that abnormal fetal heart rate patterns are tightly linked to poor long-term outcome. But that isn’t true. For one thing, insufficient oxygen during labor isn’t a major cause of disability or death.20 For another, the chain between fetal heart rate abnormalities and severe adverse outcomes is weak at every link. Abnormal fetal heart rate connects weakly with condition at birth,1, 2, 7, 17, 19, 21, 23, 27, 32, 37 which connects weakly with neurologic symptoms at birth,10, 13, 17, 18, 21, 38 which connects weakly with death or permanent impairment.29 If every intermediary link in the chain is weak, then the link between abnormal fetal heart rate and severe adverse outcome is pretty much nonexistent.
There are other issues as well:
If the theory behind continuous monitoring is unsound, attempts to fix it amount to rearranging deck chairs on the Titanic.
We’ve looked at the research, which disconfirms continuous monitoring, and disproved the theory behind it. Now, let’s turn to what obstetric authorities recommend.
What Do Fetal Monitoring Guidelines Recommend?
Fetal monitoring guidelines issued by authoritative sources are in line with the evidence:
“For a woman who is at term in spontaneous labor with a fetus in vertex presentation, labor management may be individualized (depending on maternal and fetal condition and risks) to include techniques such as intermittent auscultation.” — American College of Obstetricians & Gynecologists (2019)
“Implement intermittent monitoring policies for low-risk women.” — California Maternal Quality Care Collaborative (2016)
“Do not perform cardiotocography for low-risk women in established labour.” — Royal College of Obstetricians & Gynaecologists (U.K.) (2014)
“Routine use of cardiotocography is not recommended.” — Queensland, Australia Government (2018)
“Monitor pregnancies greater than 37 weeks 0 days’ gestation in healthy women in spontaneous labor without perinatal risk factors via intermittent auscultation.” — Society of Obstetricians & Gynecologists of Canada (2020)
“Continuous cardiotocography is not recommended for assessment of fetal well-being in healthy pregnant women undergoing spontaneous labour.” — World Health Organization (2018)
Clearly, the obstetric establishment cannot claim ignorance of routine continuous monitoring’s failure. Yet despite the original research finding no benefits, later research showing that modifications don’t change that fact, the provably false premise of the theory, and authoritative fetal monitoring guidelines rejecting routine continuous fetal monitoring, it remains standard practice in most hospitals, which brings us to . . .
Because continuous fetal monitoring remains the norm, you have your work cut out for you if you want to minimize unnecessary exposure to it. Here are some ways to do that:
Strategies during pregnancy: Hopefully, you are reading this early enough in pregnancy that you are still exploring your options, but if you are further along, don’t be afraid to make a switch if you realize that the care isn’t what you want. It’s almost always a better choice than sticking with what you’ve got and hoping for the best.
Strategies during labor:
Provided you and your baby are healthy and labor begins on its own, politely . . .
But what if the battle seems likely to generate more ill will than you are willing to risk?
Strategies for making an informed decision:
What if your care provider wants to switch to continuous monitoring?
What if your care provider wants to switch to internal monitoring?
Strategies to minimize the harms of continuous monitoring:
Sometimes continuous monitoring is indicated—or cannot be avoided without being labeled as a “difficult patient.” Here are some ways to minimize its potential harms:
Strategies to minimize harms when there is concern about fetal status:
When there is concern about the baby, here are some strategies that can help minimize harms and confirm that the concern is justified:
Taking a Deeper Dive
Why has routine continuous fetal monitoring persisted when decades of evidence show it doesn’t work?
Several motivations drive continued use of continuous fetal monitoring, none of which relate to improving maternal and child health.
Fetal Monitoring Guidelines
American College of Obstetricians & Gynecologists. ACOG Committee Opinion No. 766: Approaches to Limit Intervention During Labor and Birth. Obstet Gynecol 2019;133(2):e164-e73.
Dore S, Ehman W. Society of Obstetricians & Gynecologists of Canada No. 396-Fetal Health Surveillance: Intrapartum Consensus Guideline. J Obstet Gynaecol Can 2020;42(3):316-48 e9.
National Institute for Health & Care Excellence (NICE). Intrapartum care. Care of healthy women and their babies during childbirth; 2014.
Queensland Clinical Guidelines. Normal Birth. Queensland, AU; 2017.
Smith H, Peterson N, Lagrew D, et al. Toolkit to Support Vaginal Birth and Reduce Primary Cesareans: A Quality Improvement Toolkit. Stanford, CA: California Maternal Quality Care Collaborative; 2016.
World Health Organization. WHO Recommendations. Intrapartum Care for a Positive Childbirth Experience. Geneva: World Health Organization; 2018.
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20. MacLennan AH, Thompson SC, Gecz J. Cerebral palsy: causes, pathways, and the role of genetic variants. Am J Obstet Gynecol 2015;213(6):779-88.
21. Milsom I, Ladfors L, Thiringer K, et al. Influence of maternal, obstetric and fetal risk factors on the prevalence of birth asphyxia at term in a Swedish urban population. Acta Obstet Gynecol Scand 2002;81(10):909-17.
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27. Parer JT, King T, Flanders S, et al. Fetal acidemia and electronic fetal heart rate patterns: is there evidence of an association? J Matern Fetal Neonatal Med 2006;19(5):289-94.
28. Philipson EH, Kalhan SC, Riha MM, et al. Effects of maternal glucose infusion on fetal acid-base status in human pregnancy. Am J Obstet Gynecol 1987;157(4 Pt 1):866-73.
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30. Rathore AM, Ramji S, Devi CB, et al. Fetal scalp stimulation test: an adjunct to intermittent auscultation in non-reassuring fetal status during labor. J Obstet Gynaecol Res 2011;37(7):819-24.
31. Rhose S, Heinis AM, Vandenbussche F, et al. Inter- and intra-observer agreement of non-reassuring cardiotocography analysis and subsequent clinical management. Acta Obstet Gynecol Scand 2014;93(6):596-602.
32. Sameshima H, Ikenoue T, Ikeda T, et al. Unselected low-risk pregnancies and the effect of continuous intrapartum fetal heart rate monitoring on umbilical blood gases and cerebral palsy. Am J Obstet Gynecol 2004;190(1):118-23.
33. Smith V, Begley CM, Clarke M, et al. Professionals’ views of fetal monitoring during labour: a systematic review and thematic analysis. BMC Pregnancy Childbirth 2012;12:166.
34. Stout MJ, Cahill AG. Electronic fetal monitoring: past, present, and future. Clin Perinatol 2011;38(1):127-42, vii.
35. Stratton JF, Stronge J, Boylan PC. Hyponatraemia and non-electrolyte solutions in labouring primigravida. Eur J Obstet Gynecol Reprod Biol 1995;59(2):149-51.
36. West CR, Harding JE. Maternal water intoxication as a cause of neonatal seizures. J Paediatr Child Health 2004;40(12):709-10.
37. Williams KP, Galerneau F. Intrapartum fetal heart rate patterns in the prediction of neonatal acidemia. Am J Obstet Gynecol 2003;188(3):820-3.
38. Yeh P, Emary K, Impey L. The relationship between umbilical cord arterial pH and serious adverse neonatal outcome: analysis of 51,519 consecutive validated samples. BJOG 2012;119(7):824-31.