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Prenatal care always has been in part about identifying women with medical complications including preeclampsia. We have long measured blood pressure, checked the urine for high levels of protein, and monitored weight gain. We still do.
However, over the years, the diagnostic criteria for preeclampsia have evolved, first with the exclusion of edema and more recently with the exclusion of proteinuria as a necessary element of the diagnosis. The American College of Obstetricians and Gynecologists’ Task Force Report, Hypertension in Pregnancy, published in 2013, concluded that while preeclampsia may still be defined by the occurrence of hypertension with proteinuria, it also may be diagnosed when hypertension occurs in association with other multisystemic signs indicative of disease severity. The change came based on evidence that some women develop eclampsia, HELLP syndrome, and other serious complications in the absence of proteinuria.
The 2013 document also attempted to review and clarify various issues relating to the classifications, diagnosis, prediction and prevention, and management of hypertension during pregnancy, including the postpartum period. In many respects, it was successful in doing so. However, there is still much confusion regarding the diagnosis of certain categories of hypertensive disorders – particularly preeclampsia with severe features and superimposed preeclampsia with or without severe features.
While it is difficult to establish precise definitions given the often insidious nature of preeclampsia, it still is important to achieve a higher level of clarity with respect to these categories. Overdiagnosis may be preferable. However, improper classification also may influence management decisions that could prove detrimental to the fetus.
Severe gestational hypertension
ACOG’s 2013 Report on Hypertension in Pregnancy classifies hypertensive disorders of pregnancy into these categories: Gestational hypertension (GHTN), preeclampsia, preeclampsia with severe features (this includes HELLP), chronic hypertension (CHTN), superimposed preeclampsia with or without severe features, and eclampsia.
Some of the definitions and diagnostic criteria are clear. For instance, GHTN is defined as the new onset of hypertension after 20 weeks’ gestation in the absence of proteinuria or systemic findings such as thrombocytopenia or impaired liver function. CHTN is defined as hypertension that predates conception or is detected before 20 weeks’ gestation. In both cases there should be elevated blood pressure on two occasions at least 4 hours apart.
A major omission is the lack of a definition for severe GHTN. Removal of this previously well-understood classification category combined with unclear statements regarding preeclampsia with or without severe features has made it difficult for physicians to know in some cases of severe hypertension only what diagnosis a woman should receive and how she should be managed.
I recommend that we maintain the category of severe GHTN, and that it be defined as a systolic blood pressure (BP) greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg on at least two occasions at least 4 hours apart when antihypertensive medications have not been initiated. There should be no proteinuria or severe features such as thrombocytopenia or impaired liver function.
The physician may elect in these cases to administer antihypertensive medication and observe the patient in the hospital. An individualized decision can then be made regarding how the patient should be managed, including whether she should be admitted and whether the pregnancy should continue beyond 34 weeks. Blood pressure, gestational age at diagnosis, the presence or absence of symptoms, and laboratory tests all should be taken into consideration.
Preeclampsia with or without severe features
We need to clarify and simplify how we think about GHTN and preeclampsia with or without severe features.
Most cases of preeclampsia will involve new-onset proteinuria, with proteinuria being defined as greater than or equal to 300 mg/day or a protein-creatinine ratio of greater than or equal to 0.3 mg/dL. In cases in which a dipstick test must be used, proteinuria is suggested by a urine protein reading of 1+. (It is important to note that dipstick readings should be taken on two separate occasions.) According to the report, preeclampsia also may be established by the presence of GHTN in association with any one of a list of features that are generally referred to as “severe features.”
Various boxes and textual descriptions in the report offer a sometimes confusing picture, however, of the terms preeclampsia and preeclampsia with severe features and their differences. For clarification, I recommend that we define preeclampsia with severe features as GHTN (mild or severe) in association with any one of the severe features.
Severe features of preeclampsia
- Platelet count less than 100,000/microliter.
- Elevated hepatic transaminases greater than two times the upper limit of normal for specific laboratory adult reference ranges.
- Severe persistent right upper quadrant abdominal pain or epigastric pain unresponsive to analgesics and unexplained by other etiology.
- Serum creatinine greater than 1.1 mg/dL.
- Pulmonary edema.
- Persistent cerebral disturbances such as severe persistent new-onset headaches unresponsive to nonnarcotic analgesics, altered mental status or other neurologic deficits.
- Visual disturbances such as blurred vision, scotomata, photophobia, or loss of vision.
I also suggest that we think of “mild” GHTN (systolic BP of 140-159 mm Hg or diastolic BP 90-109 mm Hg) and preeclampsia without severe features as one in the same, and that we manage them similarly. The presence or absence of proteinuria is currently the only difference diagnostically. The only difference with respect to management – aside from a weekly urine protein check in the case of GHTN – is the frequency of nonstress testing (NST) and amniotic fluid index (AFI) measurement (currently once a week for GHTN and twice a week for preeclampsia).
Given that unnecessary time and energy may be spent differentiating the two when management is essentially the same, I suggest that preeclampsia be diagnosed in any patient with GHTN with or without proteinuria. All patients can then be managed with blood pressure checks twice a week; symptoms and kick count daily; NST and AFI twice a week; estimated fetal weight by ultrasound every third week; lab tests (CBC, liver enzymes, and creatinine) once a week, and delivery at 37 weeks.
Superimposed preeclampsia with or without severe features
As the report states, the recognition of preeclampsia superimposed on chronic hypertension is “perhaps the greatest challenge” in the diagnosis and management of hypertensive disorders in pregnancy. Overdiagnosis “may be preferable,” the report says, given the high risk of adverse pregnancy outcomes with superimposed preeclampsia. On the other hand, it says, a “more stratified approach based on severity and predictors of adverse outcome may be useful” in avoiding unnecessary preterm births.
Ultimately, the task force proposed that we utilize the two categories of “superimposed preeclampsia” and “superimposed preeclampsia with severe features,” and in doing so, it noted that there “often is ambiguity in the diagnosis of superimposed preeclampsia and that the clinical spectrum of disease is broad.” Indeed, the diagnosis of superimposed preeclampsia as presented in the report remains vague and open to interpretation. In my institution, it has created significant confusion.
The report states that superimposed preeclampsia is likely when any of the following are present: 1) a sudden increase in blood pressure that was previously well controlled or escalation of antihypertensive medications to control blood pressure, or 2) new onset of proteinuria or a sudden increase in proteinuria in a woman with known proteinuria before or early in pregnancy.
It is not clear, however, what is considered a sudden increase in blood pressure, and it is concerning that any escalation of medication could potentially prompt this diagnosis. Is an increase in systolic blood pressure from 140 mm Hg to 150 mm Hg or an increase in diastolic blood pressure from 90 mm Hg to 100 mm Hg between two prenatal visits considered a “sudden increase”? Does an increase in methyldopa dosage from 250 mg daily to 500 mg daily to keep blood pressure within the range of mild hypertension mean that the patient should be diagnosed with superimposed preeclampsia? Hypertension is likely to increase and require an escalation of antihypertensive medications as patients with chronic hypertension progress through their pregnancies.
Similarly, a “sudden increase in proteinuria” – or “sudden, substantial, and sustained increases in protein excretion,” as written elsewhere in the report with respect to superimposed preeclampsia – also is undefined. What exactly does this mean? That we lack clinically meaningful parameters and clear descriptions of acceptable criteria/scenarios for observation rather than intervention is troubling, particularly because some of these women may have preexisting renal disease with expected increases and fluctuations in protein excretion during advanced gestation.
We must be cautious about making a diagnosis of superimposed preeclampsia based on changes in blood pressure or urinary protein alone, lest we have unnecessary hospitalizations and interventions. I recommend that the diagnosis of superimposed preeclampsia be made based on either the new onset of proteinuria in association with mild hypertension after 20 weeks or on elevation in blood pressure to severe ranges (systolic BP greater than or equal to160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg) despite the use of maximum doses of one antihypertensive drug.
Regarding superimposed preeclampsia with severe features, I recommend that in the case of blood pressure elevation, it be diagnosed only after maximal doses of two medications have been used. Specifically, I recommend that superimposed preeclampsia with severe features be defined as either CHTN or superimposed preeclampsia in association with either systolic BP greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg on at least two occasions despite use of maximum doses of labetalol (2,400 mg/day) plus long-acting nifedipine (120 mg/day), or with any of the other severe features.
In a second installment of the Master Class, I will elaborate on the treatment of severe GHTN and address the management of preeclampsia with severe features as well as postpartum management of hypertension during pregnancy.
Suggested diagnostic definitions
- Preeclampsia with severe features: GHTN in association with severe features.
- Superimposed preeclampsia: CHTN with either the new onset of proteinuria in association with mild hypertension after 20 weeks, or an elevation in blood pressure to severe ranges (systolic BP greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg) despite the use of the maximal dose of one antihypertensive drug.
- Superimposed preeclampsia with severe features: CHTN or superimposed preeclampsia with severe features or with a rise in blood pressure to severe ranges despite the maximal doses of two antihypertensive drugs (e.g. 2,400 mg/day labetalol plus 120 mg/day long-acting nifedipine).
Note: These definitions reflect adaptations and clarifications of ACOG’s 2013 Task Force Report on Hypertension in Pregnancy.
Dr. Sibai is professor of obstetrics, gynecology, and reproductive sciences at the University of Texas McGovern Medical School, Houston.
Prenatal care always has been in part about identifying women with medical complications including preeclampsia. We have long measured blood pressure, checked the urine for high levels of protein, and monitored weight gain. We still do.
However, over the years, the diagnostic criteria for preeclampsia have evolved, first with the exclusion of edema and more recently with the exclusion of proteinuria as a necessary element of the diagnosis. The American College of Obstetricians and Gynecologists’ Task Force Report, Hypertension in Pregnancy, published in 2013, concluded that while preeclampsia may still be defined by the occurrence of hypertension with proteinuria, it also may be diagnosed when hypertension occurs in association with other multisystemic signs indicative of disease severity. The change came based on evidence that some women develop eclampsia, HELLP syndrome, and other serious complications in the absence of proteinuria.
The 2013 document also attempted to review and clarify various issues relating to the classifications, diagnosis, prediction and prevention, and management of hypertension during pregnancy, including the postpartum period. In many respects, it was successful in doing so. However, there is still much confusion regarding the diagnosis of certain categories of hypertensive disorders – particularly preeclampsia with severe features and superimposed preeclampsia with or without severe features.
While it is difficult to establish precise definitions given the often insidious nature of preeclampsia, it still is important to achieve a higher level of clarity with respect to these categories. Overdiagnosis may be preferable. However, improper classification also may influence management decisions that could prove detrimental to the fetus.
Severe gestational hypertension
ACOG’s 2013 Report on Hypertension in Pregnancy classifies hypertensive disorders of pregnancy into these categories: Gestational hypertension (GHTN), preeclampsia, preeclampsia with severe features (this includes HELLP), chronic hypertension (CHTN), superimposed preeclampsia with or without severe features, and eclampsia.
Some of the definitions and diagnostic criteria are clear. For instance, GHTN is defined as the new onset of hypertension after 20 weeks’ gestation in the absence of proteinuria or systemic findings such as thrombocytopenia or impaired liver function. CHTN is defined as hypertension that predates conception or is detected before 20 weeks’ gestation. In both cases there should be elevated blood pressure on two occasions at least 4 hours apart.
A major omission is the lack of a definition for severe GHTN. Removal of this previously well-understood classification category combined with unclear statements regarding preeclampsia with or without severe features has made it difficult for physicians to know in some cases of severe hypertension only what diagnosis a woman should receive and how she should be managed.
I recommend that we maintain the category of severe GHTN, and that it be defined as a systolic blood pressure (BP) greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg on at least two occasions at least 4 hours apart when antihypertensive medications have not been initiated. There should be no proteinuria or severe features such as thrombocytopenia or impaired liver function.
The physician may elect in these cases to administer antihypertensive medication and observe the patient in the hospital. An individualized decision can then be made regarding how the patient should be managed, including whether she should be admitted and whether the pregnancy should continue beyond 34 weeks. Blood pressure, gestational age at diagnosis, the presence or absence of symptoms, and laboratory tests all should be taken into consideration.
Preeclampsia with or without severe features
We need to clarify and simplify how we think about GHTN and preeclampsia with or without severe features.
Most cases of preeclampsia will involve new-onset proteinuria, with proteinuria being defined as greater than or equal to 300 mg/day or a protein-creatinine ratio of greater than or equal to 0.3 mg/dL. In cases in which a dipstick test must be used, proteinuria is suggested by a urine protein reading of 1+. (It is important to note that dipstick readings should be taken on two separate occasions.) According to the report, preeclampsia also may be established by the presence of GHTN in association with any one of a list of features that are generally referred to as “severe features.”
Various boxes and textual descriptions in the report offer a sometimes confusing picture, however, of the terms preeclampsia and preeclampsia with severe features and their differences. For clarification, I recommend that we define preeclampsia with severe features as GHTN (mild or severe) in association with any one of the severe features.
Severe features of preeclampsia
- Platelet count less than 100,000/microliter.
- Elevated hepatic transaminases greater than two times the upper limit of normal for specific laboratory adult reference ranges.
- Severe persistent right upper quadrant abdominal pain or epigastric pain unresponsive to analgesics and unexplained by other etiology.
- Serum creatinine greater than 1.1 mg/dL.
- Pulmonary edema.
- Persistent cerebral disturbances such as severe persistent new-onset headaches unresponsive to nonnarcotic analgesics, altered mental status or other neurologic deficits.
- Visual disturbances such as blurred vision, scotomata, photophobia, or loss of vision.
I also suggest that we think of “mild” GHTN (systolic BP of 140-159 mm Hg or diastolic BP 90-109 mm Hg) and preeclampsia without severe features as one in the same, and that we manage them similarly. The presence or absence of proteinuria is currently the only difference diagnostically. The only difference with respect to management – aside from a weekly urine protein check in the case of GHTN – is the frequency of nonstress testing (NST) and amniotic fluid index (AFI) measurement (currently once a week for GHTN and twice a week for preeclampsia).
Given that unnecessary time and energy may be spent differentiating the two when management is essentially the same, I suggest that preeclampsia be diagnosed in any patient with GHTN with or without proteinuria. All patients can then be managed with blood pressure checks twice a week; symptoms and kick count daily; NST and AFI twice a week; estimated fetal weight by ultrasound every third week; lab tests (CBC, liver enzymes, and creatinine) once a week, and delivery at 37 weeks.
Superimposed preeclampsia with or without severe features
As the report states, the recognition of preeclampsia superimposed on chronic hypertension is “perhaps the greatest challenge” in the diagnosis and management of hypertensive disorders in pregnancy. Overdiagnosis “may be preferable,” the report says, given the high risk of adverse pregnancy outcomes with superimposed preeclampsia. On the other hand, it says, a “more stratified approach based on severity and predictors of adverse outcome may be useful” in avoiding unnecessary preterm births.
Ultimately, the task force proposed that we utilize the two categories of “superimposed preeclampsia” and “superimposed preeclampsia with severe features,” and in doing so, it noted that there “often is ambiguity in the diagnosis of superimposed preeclampsia and that the clinical spectrum of disease is broad.” Indeed, the diagnosis of superimposed preeclampsia as presented in the report remains vague and open to interpretation. In my institution, it has created significant confusion.
The report states that superimposed preeclampsia is likely when any of the following are present: 1) a sudden increase in blood pressure that was previously well controlled or escalation of antihypertensive medications to control blood pressure, or 2) new onset of proteinuria or a sudden increase in proteinuria in a woman with known proteinuria before or early in pregnancy.
It is not clear, however, what is considered a sudden increase in blood pressure, and it is concerning that any escalation of medication could potentially prompt this diagnosis. Is an increase in systolic blood pressure from 140 mm Hg to 150 mm Hg or an increase in diastolic blood pressure from 90 mm Hg to 100 mm Hg between two prenatal visits considered a “sudden increase”? Does an increase in methyldopa dosage from 250 mg daily to 500 mg daily to keep blood pressure within the range of mild hypertension mean that the patient should be diagnosed with superimposed preeclampsia? Hypertension is likely to increase and require an escalation of antihypertensive medications as patients with chronic hypertension progress through their pregnancies.
Similarly, a “sudden increase in proteinuria” – or “sudden, substantial, and sustained increases in protein excretion,” as written elsewhere in the report with respect to superimposed preeclampsia – also is undefined. What exactly does this mean? That we lack clinically meaningful parameters and clear descriptions of acceptable criteria/scenarios for observation rather than intervention is troubling, particularly because some of these women may have preexisting renal disease with expected increases and fluctuations in protein excretion during advanced gestation.
We must be cautious about making a diagnosis of superimposed preeclampsia based on changes in blood pressure or urinary protein alone, lest we have unnecessary hospitalizations and interventions. I recommend that the diagnosis of superimposed preeclampsia be made based on either the new onset of proteinuria in association with mild hypertension after 20 weeks or on elevation in blood pressure to severe ranges (systolic BP greater than or equal to160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg) despite the use of maximum doses of one antihypertensive drug.
Regarding superimposed preeclampsia with severe features, I recommend that in the case of blood pressure elevation, it be diagnosed only after maximal doses of two medications have been used. Specifically, I recommend that superimposed preeclampsia with severe features be defined as either CHTN or superimposed preeclampsia in association with either systolic BP greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg on at least two occasions despite use of maximum doses of labetalol (2,400 mg/day) plus long-acting nifedipine (120 mg/day), or with any of the other severe features.
In a second installment of the Master Class, I will elaborate on the treatment of severe GHTN and address the management of preeclampsia with severe features as well as postpartum management of hypertension during pregnancy.
Suggested diagnostic definitions
- Preeclampsia with severe features: GHTN in association with severe features.
- Superimposed preeclampsia: CHTN with either the new onset of proteinuria in association with mild hypertension after 20 weeks, or an elevation in blood pressure to severe ranges (systolic BP greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg) despite the use of the maximal dose of one antihypertensive drug.
- Superimposed preeclampsia with severe features: CHTN or superimposed preeclampsia with severe features or with a rise in blood pressure to severe ranges despite the maximal doses of two antihypertensive drugs (e.g. 2,400 mg/day labetalol plus 120 mg/day long-acting nifedipine).
Note: These definitions reflect adaptations and clarifications of ACOG’s 2013 Task Force Report on Hypertension in Pregnancy.
Dr. Sibai is professor of obstetrics, gynecology, and reproductive sciences at the University of Texas McGovern Medical School, Houston.
Prenatal care always has been in part about identifying women with medical complications including preeclampsia. We have long measured blood pressure, checked the urine for high levels of protein, and monitored weight gain. We still do.
However, over the years, the diagnostic criteria for preeclampsia have evolved, first with the exclusion of edema and more recently with the exclusion of proteinuria as a necessary element of the diagnosis. The American College of Obstetricians and Gynecologists’ Task Force Report, Hypertension in Pregnancy, published in 2013, concluded that while preeclampsia may still be defined by the occurrence of hypertension with proteinuria, it also may be diagnosed when hypertension occurs in association with other multisystemic signs indicative of disease severity. The change came based on evidence that some women develop eclampsia, HELLP syndrome, and other serious complications in the absence of proteinuria.
The 2013 document also attempted to review and clarify various issues relating to the classifications, diagnosis, prediction and prevention, and management of hypertension during pregnancy, including the postpartum period. In many respects, it was successful in doing so. However, there is still much confusion regarding the diagnosis of certain categories of hypertensive disorders – particularly preeclampsia with severe features and superimposed preeclampsia with or without severe features.
While it is difficult to establish precise definitions given the often insidious nature of preeclampsia, it still is important to achieve a higher level of clarity with respect to these categories. Overdiagnosis may be preferable. However, improper classification also may influence management decisions that could prove detrimental to the fetus.
Severe gestational hypertension
ACOG’s 2013 Report on Hypertension in Pregnancy classifies hypertensive disorders of pregnancy into these categories: Gestational hypertension (GHTN), preeclampsia, preeclampsia with severe features (this includes HELLP), chronic hypertension (CHTN), superimposed preeclampsia with or without severe features, and eclampsia.
Some of the definitions and diagnostic criteria are clear. For instance, GHTN is defined as the new onset of hypertension after 20 weeks’ gestation in the absence of proteinuria or systemic findings such as thrombocytopenia or impaired liver function. CHTN is defined as hypertension that predates conception or is detected before 20 weeks’ gestation. In both cases there should be elevated blood pressure on two occasions at least 4 hours apart.
A major omission is the lack of a definition for severe GHTN. Removal of this previously well-understood classification category combined with unclear statements regarding preeclampsia with or without severe features has made it difficult for physicians to know in some cases of severe hypertension only what diagnosis a woman should receive and how she should be managed.
I recommend that we maintain the category of severe GHTN, and that it be defined as a systolic blood pressure (BP) greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg on at least two occasions at least 4 hours apart when antihypertensive medications have not been initiated. There should be no proteinuria or severe features such as thrombocytopenia or impaired liver function.
The physician may elect in these cases to administer antihypertensive medication and observe the patient in the hospital. An individualized decision can then be made regarding how the patient should be managed, including whether she should be admitted and whether the pregnancy should continue beyond 34 weeks. Blood pressure, gestational age at diagnosis, the presence or absence of symptoms, and laboratory tests all should be taken into consideration.
Preeclampsia with or without severe features
We need to clarify and simplify how we think about GHTN and preeclampsia with or without severe features.
Most cases of preeclampsia will involve new-onset proteinuria, with proteinuria being defined as greater than or equal to 300 mg/day or a protein-creatinine ratio of greater than or equal to 0.3 mg/dL. In cases in which a dipstick test must be used, proteinuria is suggested by a urine protein reading of 1+. (It is important to note that dipstick readings should be taken on two separate occasions.) According to the report, preeclampsia also may be established by the presence of GHTN in association with any one of a list of features that are generally referred to as “severe features.”
Various boxes and textual descriptions in the report offer a sometimes confusing picture, however, of the terms preeclampsia and preeclampsia with severe features and their differences. For clarification, I recommend that we define preeclampsia with severe features as GHTN (mild or severe) in association with any one of the severe features.
Severe features of preeclampsia
- Platelet count less than 100,000/microliter.
- Elevated hepatic transaminases greater than two times the upper limit of normal for specific laboratory adult reference ranges.
- Severe persistent right upper quadrant abdominal pain or epigastric pain unresponsive to analgesics and unexplained by other etiology.
- Serum creatinine greater than 1.1 mg/dL.
- Pulmonary edema.
- Persistent cerebral disturbances such as severe persistent new-onset headaches unresponsive to nonnarcotic analgesics, altered mental status or other neurologic deficits.
- Visual disturbances such as blurred vision, scotomata, photophobia, or loss of vision.
I also suggest that we think of “mild” GHTN (systolic BP of 140-159 mm Hg or diastolic BP 90-109 mm Hg) and preeclampsia without severe features as one in the same, and that we manage them similarly. The presence or absence of proteinuria is currently the only difference diagnostically. The only difference with respect to management – aside from a weekly urine protein check in the case of GHTN – is the frequency of nonstress testing (NST) and amniotic fluid index (AFI) measurement (currently once a week for GHTN and twice a week for preeclampsia).
Given that unnecessary time and energy may be spent differentiating the two when management is essentially the same, I suggest that preeclampsia be diagnosed in any patient with GHTN with or without proteinuria. All patients can then be managed with blood pressure checks twice a week; symptoms and kick count daily; NST and AFI twice a week; estimated fetal weight by ultrasound every third week; lab tests (CBC, liver enzymes, and creatinine) once a week, and delivery at 37 weeks.
Superimposed preeclampsia with or without severe features
As the report states, the recognition of preeclampsia superimposed on chronic hypertension is “perhaps the greatest challenge” in the diagnosis and management of hypertensive disorders in pregnancy. Overdiagnosis “may be preferable,” the report says, given the high risk of adverse pregnancy outcomes with superimposed preeclampsia. On the other hand, it says, a “more stratified approach based on severity and predictors of adverse outcome may be useful” in avoiding unnecessary preterm births.
Ultimately, the task force proposed that we utilize the two categories of “superimposed preeclampsia” and “superimposed preeclampsia with severe features,” and in doing so, it noted that there “often is ambiguity in the diagnosis of superimposed preeclampsia and that the clinical spectrum of disease is broad.” Indeed, the diagnosis of superimposed preeclampsia as presented in the report remains vague and open to interpretation. In my institution, it has created significant confusion.
The report states that superimposed preeclampsia is likely when any of the following are present: 1) a sudden increase in blood pressure that was previously well controlled or escalation of antihypertensive medications to control blood pressure, or 2) new onset of proteinuria or a sudden increase in proteinuria in a woman with known proteinuria before or early in pregnancy.
It is not clear, however, what is considered a sudden increase in blood pressure, and it is concerning that any escalation of medication could potentially prompt this diagnosis. Is an increase in systolic blood pressure from 140 mm Hg to 150 mm Hg or an increase in diastolic blood pressure from 90 mm Hg to 100 mm Hg between two prenatal visits considered a “sudden increase”? Does an increase in methyldopa dosage from 250 mg daily to 500 mg daily to keep blood pressure within the range of mild hypertension mean that the patient should be diagnosed with superimposed preeclampsia? Hypertension is likely to increase and require an escalation of antihypertensive medications as patients with chronic hypertension progress through their pregnancies.
Similarly, a “sudden increase in proteinuria” – or “sudden, substantial, and sustained increases in protein excretion,” as written elsewhere in the report with respect to superimposed preeclampsia – also is undefined. What exactly does this mean? That we lack clinically meaningful parameters and clear descriptions of acceptable criteria/scenarios for observation rather than intervention is troubling, particularly because some of these women may have preexisting renal disease with expected increases and fluctuations in protein excretion during advanced gestation.
We must be cautious about making a diagnosis of superimposed preeclampsia based on changes in blood pressure or urinary protein alone, lest we have unnecessary hospitalizations and interventions. I recommend that the diagnosis of superimposed preeclampsia be made based on either the new onset of proteinuria in association with mild hypertension after 20 weeks or on elevation in blood pressure to severe ranges (systolic BP greater than or equal to160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg) despite the use of maximum doses of one antihypertensive drug.
Regarding superimposed preeclampsia with severe features, I recommend that in the case of blood pressure elevation, it be diagnosed only after maximal doses of two medications have been used. Specifically, I recommend that superimposed preeclampsia with severe features be defined as either CHTN or superimposed preeclampsia in association with either systolic BP greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg on at least two occasions despite use of maximum doses of labetalol (2,400 mg/day) plus long-acting nifedipine (120 mg/day), or with any of the other severe features.
In a second installment of the Master Class, I will elaborate on the treatment of severe GHTN and address the management of preeclampsia with severe features as well as postpartum management of hypertension during pregnancy.
Suggested diagnostic definitions
- Preeclampsia with severe features: GHTN in association with severe features.
- Superimposed preeclampsia: CHTN with either the new onset of proteinuria in association with mild hypertension after 20 weeks, or an elevation in blood pressure to severe ranges (systolic BP greater than or equal to 160 mm Hg and/or diastolic BP greater than or equal to 110 mm Hg) despite the use of the maximal dose of one antihypertensive drug.
- Superimposed preeclampsia with severe features: CHTN or superimposed preeclampsia with severe features or with a rise in blood pressure to severe ranges despite the maximal doses of two antihypertensive drugs (e.g. 2,400 mg/day labetalol plus 120 mg/day long-acting nifedipine).
Note: These definitions reflect adaptations and clarifications of ACOG’s 2013 Task Force Report on Hypertension in Pregnancy.
Dr. Sibai is professor of obstetrics, gynecology, and reproductive sciences at the University of Texas McGovern Medical School, Houston.