- Email: [email protected]
Three-tier versus five-tier fetal heart rate classification systems
Letters to the Editors 0.427 ppm, which confirms that white tuna should not be considered a low-mercury fish.7 The fish consumption message is indeed complex, as Dr Brenna points out. Our aim is to simplify the message as much as possible for patients while still considering important health benefits. We want to encourage women to eat healthy fish but to choose wisely when doing so. This counseling will help keep women healthy during pregnancy while lowering mercury exposures that can affect the developing fetus adversely. f Sheela Sathyanarayana, MD, MPH Department of Pediatrics Seattle Children’s Research Institute University of Washington Judith Focareta, Med, RN Magee-Womens Hospital Pittsburgh, PA Tanya Dailey, MD Women & Infants Hospital The Warren Alpert Medical School of Brown University Providence, RI Susan Buchanan, MD, MPH Environmental and Occupational Health Sciences University of Illinois at Chicago School of Public Health The authors report no conflict of interest.
www.AJOG.org REFERENCES 1. Sathyanarayana S, Focareta J, Dailey T, Buchanan S. Environmental exposures: how to counsel preconception and prenatal patients in the clinical setting. Am J Obstet Gynecol 2012. Epub ahead of print. 2. Minnesota Department of Health. Available at: http://www.health. state.mn.us/divs/eh/fish/eating/safeeating.html. Accessed May 2, 2012. 3. Michigan Department of Community Health. Available at: http://www. michigan.gov/documents/mdch/2011-05-26_-_MERCURY_ADVISORY_ FLYER_STORE-BOUGHT_FISH__RESTAURANT_WEB_354266_7.pdf. Accessed May 2, 2012. 4. Washington State Department of Health. Available at: http://www.doh. wa.gov/ehp/oehas/fish/fishadvmerc.htm. Accessed May 2, 2012. 5. State of California Office of Environmental Health Hazard Assessment. Available at: http://oehha.ca.gov/fish/pdf/2011CommFishGuide_color. pdf. Accessed May 2, 2012. 6. United States Food and Drug Administration. Food Safety. Mercury Levels in Commercial Fish and Shellfish (1990-2010). Available at: http:// www.fda.gov/Food/FoodSafety/Product-SpecificInformation/Seafood/ FoodbornePathogensContaminants/Methylmercury/ucm115644.htm. Accessed May 2, 2012. 7. Consumer Reports magazine: January 2011. Mercury in canned tuna still a concern, New tests reinforce a need for some people to limit consumption. Available at: www.consumerreports.org/cro/magazine-archive/ 2011/january/food/mercury-in-tuna/overview/index.htm. Accessed May 2, 2012. © 2012 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog. 2012.07.005
Three-tier versus five-tier fetal heart rate classification systems TO THE EDITORS: We read with interest a recent article by Coletta and colleagues1 comparing the 3-tier system for fetal heart rate classification proposed by the Eunice Kennedy Shriver National Institute of Child Health and Human Development with a 5-tier color-coded system originally described by Parer and Ikeda.1-3 The authors concluded that the 5-tier system was more sensitive than the 3-tier system in the detection of acidemia. We propose a different interpretation of the data. In the 5-tier system, the green, blue, and yellow tiers were statistically indistinguishable from one another in their ability to predict acidemia. The orange and red tiers were statistically different from the other 3 tiers but were identical to one another. Consequently, the 5-tier system effectively identified only 2 distinct tiers of risk for acidemia. Tracings that were outside the combined green, blue, and yellow category accurately identified 19 of 24 acidemic neonates (sensitivity 79%), whereas tracings outside category I accurately identified 23 of 24 acidemic neonates (sensitivity 96%). From this perspective, the sensitivity of the 5-tier system was not superior to the 3-tier system but instead was slightly inferior. The authors reported that most of the tracings resulting in acidemia were category II and therefore had “no clearly defined management strategy.” Contrary to this notion, recent publications have described highly detailed management strategies for such tracings, including intrauterine resuscitative measures e8
American Journal of Obstetrics & Gynecology DECEMBER 2012
and, if not successful, consideration of delivery.2,4 Interestingly, these recommendations are identical to the management actions recommended for all tracings in the blue, yellow, and orange categories.3 As the authors noted, further research is needed to refine the existing 3-tier system. However, the solution to an imperfect yet simple 3-tier system is not to replace it with a complex, cumbersome 5-tier system that does not identify 5 categories of risk and offers no new recommendations for management. f David A. Miller, MD Department of Clinical Obstetrics, Gynecology, and Pediatrics Division of Maternal-Fetal Medicine Keck School of Medicine University of Southern California Department of Obstetrics and Gynecology Division of Maternal Fetal Medicine Children’s Hospital Los Angeles 1300 North Vermont Ave. Doctors’ Tower Suite 301 Los Angeles, CA 90027 [email protected] Lisa A. Miller, CNM, JD Perinatal Risk Management and Education Services Chicago, IL [email protected]
Letters to the Editors
www.AJOG.org D.A.M. is a consultant with Clinical Computer Systems, Inc, makers of OBIX, and a partner with GE Healthcare for online fetal monitoring education. L.A.M. is also a consultant with Clinical Computer Systems, Inc.
TABLE Variable
Sensitivity, %
Specificity, %
Category I
4.2
79.2
Green
8.3
66.7
Blue
0
75
Green or blue
8.3
58.3
...................................................................................................................................................................
REFERENCES 1. Coletta J, Murphy E, Rubeo Z, et al. The 5-tier system of assessing fetal heart rate tracings is superior to the 3-tier system in identifying fetal acidemia. Am J Obstet Gynecol 2012;206:226.e1-5. 2. American College of Obstetricians and Gynecologists. Management of intrapartum fetal heart rate tracings. ACOG practice bulletin no. 116. Obstet Gynecol 2010;116:1232-40. 3. Parer JT, Ikeda T. A framework for standardized management of intrapartum fetal heart rate patterns. Am J Obstet Gynecol 2007;197:26.e1-6. 4. Miller DA, Miller LA. Electronic fetal heart rate monitoring: applying principles of patient safety. Am J Obstet Gynecol 2012;206:278-83. © 2012 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog. 2012.07.014
REPLY Thank you for your interest in our article. Although we agree that green, blue, and yellow tracings were statistically indistinguishable, they all essentially identify fetuses unlikely to have acidemia. In contrast, there is no statistical difference between the proportion of category II tracings in the acidemic versus normal pH group (83% vs 79%, P ⫽ .99), suggesting that other characteristics of a category II tracing are needed to discriminate a healthy fetus from one in need of imminent delivery. Your additional statistical analysis prompted us to review our results.1 We found some errors in the table we sent to the journal, which we have resolved with the new table below (Table). Fortunately, this did not change our conclusions, but only strengthened them. Your publication in April’s Journal does outline additional steps for interpreting category II tracings and the subsequent recommended management.2 This adds valuable information to the literature, which was not available at the time of our publication. The breakdown of category II into the presence or absence of moderate variability is equivalent to the blue, yellow, and orange categories described by Parer and Ikeda, and
................................................................................................................................................................... ................................................................................................................................................................... ............................................................................................................................................................................
Category III
12.5
100
Orange
41.7
100
................................................................................................................................................................... ...................................................................................................................................................................
Red
37.5
100
Orange or red
79.2
100
................................................................................................................................................................... ............................................................................................................................................................................
Coletta. Reply. Am J Obstet Gynecol 2012.
may produce similar results, as suggested in our concluding statement. Finally, because the incidence of pathological acidemia was only 0.3% in our cohort of more than 9600 deliveries, we are not proposing that the 3-tier system be abandoned for the more cumbersome 5-tier classification system. However, clearly further research is needed to determine the essential criteria within a category II tracing that will identify fetal acidemia and allow for timely intervention.1 Jaclyn Coletta, MD Cynthia Gyamfi-Bannerman, MD Columbia University Medical Center Department of Obstetrics and Gynecology 622 West 168th St. PH 16-66 New York, NY 10032 REFERENCES 1. Coletta J, Murphy E, Rubeo Z, Gyamfi-Bannerman C. The 5-tier system of assessing fetal heart rate tracings is superior to the 3-tier system in identifying fetal acidemia. Am J Obstet Gynecol 2012;206:226.e1-5. 2. Miller DA, Miller LA. Electronic fetal heart rate monitoring: applying principles of patient safety. Am J Obstet Gynecol 2012;206:274-83. © 2012 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog. 2012.07.013
The study design and compliance may affect strength of inferences TO THE EDITORS: We wish to welcome the study by Upson et al1 on prognostic biomarkers of endometrial hyperplasia resistance when treated with oral progestins. We agree with the authors that the prognosis of women with endometrial hyperplasia when treated with oral progestins is underresearched and clinicians cannot reliably identify the women at risk. Oral progestins are a popular therapeutic choice, but we have shown that levongorgestrel intrauterine system (LNG-IUS) achieves higher regression rates than oral progestins.2 The intrauterine progestin release is also associated with higher patient satisfaction resulting in higher compliance, which may also explain its
better efficacy in treating endometrial hyperplasia compared with oral progestins. However, when it comes to identifying prognostic markers for response to progestin treatment of endometrial hyperplasia, patient compliance represents an important confounding factor. Accounting for this confounding is difficult, and it may dilute the prognostic accuracy of biomarkers used to predict response to treatment. Hence, we have preferred to assess a similar panel of biomarkers using the LNG-IUS in which the patient compliance is not an issue. We also wish to add that the study design may affect the estimate of prognostic accuracy. The largest effect on the DECEMBER 2012 American Journal of Obstetrics & Gynecology
e9
www.AJOG.org REFERENCES 1. Sathyanarayana S, Focareta J, Dailey T, Buchanan S. Environmental exposures: how to counsel preconception and prenatal patients in the clinical setting. Am J Obstet Gynecol 2012. Epub ahead of print. 2. Minnesota Department of Health. Available at: http://www.health. state.mn.us/divs/eh/fish/eating/safeeating.html. Accessed May 2, 2012. 3. Michigan Department of Community Health. Available at: http://www. michigan.gov/documents/mdch/2011-05-26_-_MERCURY_ADVISORY_ FLYER_STORE-BOUGHT_FISH__RESTAURANT_WEB_354266_7.pdf. Accessed May 2, 2012. 4. Washington State Department of Health. Available at: http://www.doh. wa.gov/ehp/oehas/fish/fishadvmerc.htm. Accessed May 2, 2012. 5. State of California Office of Environmental Health Hazard Assessment. Available at: http://oehha.ca.gov/fish/pdf/2011CommFishGuide_color. pdf. Accessed May 2, 2012. 6. United States Food and Drug Administration. Food Safety. Mercury Levels in Commercial Fish and Shellfish (1990-2010). Available at: http:// www.fda.gov/Food/FoodSafety/Product-SpecificInformation/Seafood/ FoodbornePathogensContaminants/Methylmercury/ucm115644.htm. Accessed May 2, 2012. 7. Consumer Reports magazine: January 2011. Mercury in canned tuna still a concern, New tests reinforce a need for some people to limit consumption. Available at: www.consumerreports.org/cro/magazine-archive/ 2011/january/food/mercury-in-tuna/overview/index.htm. Accessed May 2, 2012. © 2012 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog. 2012.07.005
Three-tier versus five-tier fetal heart rate classification systems TO THE EDITORS: We read with interest a recent article by Coletta and colleagues1 comparing the 3-tier system for fetal heart rate classification proposed by the Eunice Kennedy Shriver National Institute of Child Health and Human Development with a 5-tier color-coded system originally described by Parer and Ikeda.1-3 The authors concluded that the 5-tier system was more sensitive than the 3-tier system in the detection of acidemia. We propose a different interpretation of the data. In the 5-tier system, the green, blue, and yellow tiers were statistically indistinguishable from one another in their ability to predict acidemia. The orange and red tiers were statistically different from the other 3 tiers but were identical to one another. Consequently, the 5-tier system effectively identified only 2 distinct tiers of risk for acidemia. Tracings that were outside the combined green, blue, and yellow category accurately identified 19 of 24 acidemic neonates (sensitivity 79%), whereas tracings outside category I accurately identified 23 of 24 acidemic neonates (sensitivity 96%). From this perspective, the sensitivity of the 5-tier system was not superior to the 3-tier system but instead was slightly inferior. The authors reported that most of the tracings resulting in acidemia were category II and therefore had “no clearly defined management strategy.” Contrary to this notion, recent publications have described highly detailed management strategies for such tracings, including intrauterine resuscitative measures e8
American Journal of Obstetrics & Gynecology DECEMBER 2012
and, if not successful, consideration of delivery.2,4 Interestingly, these recommendations are identical to the management actions recommended for all tracings in the blue, yellow, and orange categories.3 As the authors noted, further research is needed to refine the existing 3-tier system. However, the solution to an imperfect yet simple 3-tier system is not to replace it with a complex, cumbersome 5-tier system that does not identify 5 categories of risk and offers no new recommendations for management. f David A. Miller, MD Department of Clinical Obstetrics, Gynecology, and Pediatrics Division of Maternal-Fetal Medicine Keck School of Medicine University of Southern California Department of Obstetrics and Gynecology Division of Maternal Fetal Medicine Children’s Hospital Los Angeles 1300 North Vermont Ave. Doctors’ Tower Suite 301 Los Angeles, CA 90027 [email protected] Lisa A. Miller, CNM, JD Perinatal Risk Management and Education Services Chicago, IL [email protected]
Letters to the Editors
www.AJOG.org D.A.M. is a consultant with Clinical Computer Systems, Inc, makers of OBIX, and a partner with GE Healthcare for online fetal monitoring education. L.A.M. is also a consultant with Clinical Computer Systems, Inc.
TABLE Variable
Sensitivity, %
Specificity, %
Category I
4.2
79.2
Green
8.3
66.7
Blue
0
75
Green or blue
8.3
58.3
...................................................................................................................................................................
REFERENCES 1. Coletta J, Murphy E, Rubeo Z, et al. The 5-tier system of assessing fetal heart rate tracings is superior to the 3-tier system in identifying fetal acidemia. Am J Obstet Gynecol 2012;206:226.e1-5. 2. American College of Obstetricians and Gynecologists. Management of intrapartum fetal heart rate tracings. ACOG practice bulletin no. 116. Obstet Gynecol 2010;116:1232-40. 3. Parer JT, Ikeda T. A framework for standardized management of intrapartum fetal heart rate patterns. Am J Obstet Gynecol 2007;197:26.e1-6. 4. Miller DA, Miller LA. Electronic fetal heart rate monitoring: applying principles of patient safety. Am J Obstet Gynecol 2012;206:278-83. © 2012 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog. 2012.07.014
REPLY Thank you for your interest in our article. Although we agree that green, blue, and yellow tracings were statistically indistinguishable, they all essentially identify fetuses unlikely to have acidemia. In contrast, there is no statistical difference between the proportion of category II tracings in the acidemic versus normal pH group (83% vs 79%, P ⫽ .99), suggesting that other characteristics of a category II tracing are needed to discriminate a healthy fetus from one in need of imminent delivery. Your additional statistical analysis prompted us to review our results.1 We found some errors in the table we sent to the journal, which we have resolved with the new table below (Table). Fortunately, this did not change our conclusions, but only strengthened them. Your publication in April’s Journal does outline additional steps for interpreting category II tracings and the subsequent recommended management.2 This adds valuable information to the literature, which was not available at the time of our publication. The breakdown of category II into the presence or absence of moderate variability is equivalent to the blue, yellow, and orange categories described by Parer and Ikeda, and
................................................................................................................................................................... ................................................................................................................................................................... ............................................................................................................................................................................
Category III
12.5
100
Orange
41.7
100
................................................................................................................................................................... ...................................................................................................................................................................
Red
37.5
100
Orange or red
79.2
100
................................................................................................................................................................... ............................................................................................................................................................................
Coletta. Reply. Am J Obstet Gynecol 2012.
may produce similar results, as suggested in our concluding statement. Finally, because the incidence of pathological acidemia was only 0.3% in our cohort of more than 9600 deliveries, we are not proposing that the 3-tier system be abandoned for the more cumbersome 5-tier classification system. However, clearly further research is needed to determine the essential criteria within a category II tracing that will identify fetal acidemia and allow for timely intervention.1 Jaclyn Coletta, MD Cynthia Gyamfi-Bannerman, MD Columbia University Medical Center Department of Obstetrics and Gynecology 622 West 168th St. PH 16-66 New York, NY 10032 REFERENCES 1. Coletta J, Murphy E, Rubeo Z, Gyamfi-Bannerman C. The 5-tier system of assessing fetal heart rate tracings is superior to the 3-tier system in identifying fetal acidemia. Am J Obstet Gynecol 2012;206:226.e1-5. 2. Miller DA, Miller LA. Electronic fetal heart rate monitoring: applying principles of patient safety. Am J Obstet Gynecol 2012;206:274-83. © 2012 Mosby, Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajog. 2012.07.013
The study design and compliance may affect strength of inferences TO THE EDITORS: We wish to welcome the study by Upson et al1 on prognostic biomarkers of endometrial hyperplasia resistance when treated with oral progestins. We agree with the authors that the prognosis of women with endometrial hyperplasia when treated with oral progestins is underresearched and clinicians cannot reliably identify the women at risk. Oral progestins are a popular therapeutic choice, but we have shown that levongorgestrel intrauterine system (LNG-IUS) achieves higher regression rates than oral progestins.2 The intrauterine progestin release is also associated with higher patient satisfaction resulting in higher compliance, which may also explain its
better efficacy in treating endometrial hyperplasia compared with oral progestins. However, when it comes to identifying prognostic markers for response to progestin treatment of endometrial hyperplasia, patient compliance represents an important confounding factor. Accounting for this confounding is difficult, and it may dilute the prognostic accuracy of biomarkers used to predict response to treatment. Hence, we have preferred to assess a similar panel of biomarkers using the LNG-IUS in which the patient compliance is not an issue. We also wish to add that the study design may affect the estimate of prognostic accuracy. The largest effect on the DECEMBER 2012 American Journal of Obstetrics & Gynecology
e9