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Does tight control of hypertension in pregnancy produce better perinatal outcomes?
The question of degree of control of hypertension during pregnancy has been debated for many years. The primary concern, which is mainly theoretical, is that tight control of hypertension may lead to underperfusion of the uterus, ultimately resulting in fetal growth restriction. This study adds to the available body of literature on this subject.
Details of the trial
In this pragmatic randomized clinical trial, 987 women with office diastolic BP of 90 to 105 mm Hg (or 85 to 105 mm Hg if they were taking a hypertensive medication) between 14 weeks, zero days of gestation and 33 weeks, 6 days of gestation were randomized to tight (n = 488) versus less-tight control of hypertension (n = 493).
Practitioners were encouraged to use labetalol for treatment. The primary outcome was pregnancy loss (miscarriage, ectopic pregnancy, pregnancy termination, stillbirth, or neonatal death) or the need for high-level neonatal care (defined as greater than normal newborn care for more than 48 hours until 28 days of life or discharge home). Secondary outcomes included serious maternal morbidity as late as 6 weeks postpartum. Statistical analysis was based on the intent-to-treat principle.
Adherence to assigned treatment was good, at approximately 75% in each arm. As stated above, the study found no differences in the combined primary endpoint between the two groups. It also found no differences in other perinatal outcomes, including small size for gestational age or other adverse neonatal outcomes. Maternal complications generally were similar as well, with the exception of severe hypertension, which was more common in the less-tight control group.
Strengths and weaknesses of the study
This trial has several important strengths, including its pragmatic design, making it more applicable to everyday practice. Other strengths include rigorous methods and a large sample size.
Two main weaknesses hamper the study, however:
- the inclusion of both chronic hypertension and gestational hypertension. In my opinion, the much more clinically relevant question concerns women with chronic hypertension, who have a long duration of treatment.
- the choice of high-level neonatal care as part of the composite endpoint. This aspect of the composite outcome drove the endpoint in terms of numbers, but it is unclear to me what its clinical relevance is. In my opinion, it is a poor surrogate for the neonatal outcomes we really care about.
What this evidence means for practice
This study does not establish a foundation for a change in clinical practice. At best, it supports the maternal safety of less-tight control of hypertension in pregnancy. That aspect of the trial may find its way into counseling of the patient.
–George Macones, MD
Share your thoughts on this article! Send your Letter to the Editor to rbarbieri@frontlinemedcom.com. Please include your name and the city and state in which you practice.
The question of degree of control of hypertension during pregnancy has been debated for many years. The primary concern, which is mainly theoretical, is that tight control of hypertension may lead to underperfusion of the uterus, ultimately resulting in fetal growth restriction. This study adds to the available body of literature on this subject.
Details of the trial
In this pragmatic randomized clinical trial, 987 women with office diastolic BP of 90 to 105 mm Hg (or 85 to 105 mm Hg if they were taking a hypertensive medication) between 14 weeks, zero days of gestation and 33 weeks, 6 days of gestation were randomized to tight (n = 488) versus less-tight control of hypertension (n = 493).
Practitioners were encouraged to use labetalol for treatment. The primary outcome was pregnancy loss (miscarriage, ectopic pregnancy, pregnancy termination, stillbirth, or neonatal death) or the need for high-level neonatal care (defined as greater than normal newborn care for more than 48 hours until 28 days of life or discharge home). Secondary outcomes included serious maternal morbidity as late as 6 weeks postpartum. Statistical analysis was based on the intent-to-treat principle.
Adherence to assigned treatment was good, at approximately 75% in each arm. As stated above, the study found no differences in the combined primary endpoint between the two groups. It also found no differences in other perinatal outcomes, including small size for gestational age or other adverse neonatal outcomes. Maternal complications generally were similar as well, with the exception of severe hypertension, which was more common in the less-tight control group.
Strengths and weaknesses of the study
This trial has several important strengths, including its pragmatic design, making it more applicable to everyday practice. Other strengths include rigorous methods and a large sample size.
Two main weaknesses hamper the study, however:
- the inclusion of both chronic hypertension and gestational hypertension. In my opinion, the much more clinically relevant question concerns women with chronic hypertension, who have a long duration of treatment.
- the choice of high-level neonatal care as part of the composite endpoint. This aspect of the composite outcome drove the endpoint in terms of numbers, but it is unclear to me what its clinical relevance is. In my opinion, it is a poor surrogate for the neonatal outcomes we really care about.
What this evidence means for practice
This study does not establish a foundation for a change in clinical practice. At best, it supports the maternal safety of less-tight control of hypertension in pregnancy. That aspect of the trial may find its way into counseling of the patient.
–George Macones, MD
Share your thoughts on this article! Send your Letter to the Editor to rbarbieri@frontlinemedcom.com. Please include your name and the city and state in which you practice.
The question of degree of control of hypertension during pregnancy has been debated for many years. The primary concern, which is mainly theoretical, is that tight control of hypertension may lead to underperfusion of the uterus, ultimately resulting in fetal growth restriction. This study adds to the available body of literature on this subject.
Details of the trial
In this pragmatic randomized clinical trial, 987 women with office diastolic BP of 90 to 105 mm Hg (or 85 to 105 mm Hg if they were taking a hypertensive medication) between 14 weeks, zero days of gestation and 33 weeks, 6 days of gestation were randomized to tight (n = 488) versus less-tight control of hypertension (n = 493).
Practitioners were encouraged to use labetalol for treatment. The primary outcome was pregnancy loss (miscarriage, ectopic pregnancy, pregnancy termination, stillbirth, or neonatal death) or the need for high-level neonatal care (defined as greater than normal newborn care for more than 48 hours until 28 days of life or discharge home). Secondary outcomes included serious maternal morbidity as late as 6 weeks postpartum. Statistical analysis was based on the intent-to-treat principle.
Adherence to assigned treatment was good, at approximately 75% in each arm. As stated above, the study found no differences in the combined primary endpoint between the two groups. It also found no differences in other perinatal outcomes, including small size for gestational age or other adverse neonatal outcomes. Maternal complications generally were similar as well, with the exception of severe hypertension, which was more common in the less-tight control group.
Strengths and weaknesses of the study
This trial has several important strengths, including its pragmatic design, making it more applicable to everyday practice. Other strengths include rigorous methods and a large sample size.
Two main weaknesses hamper the study, however:
- the inclusion of both chronic hypertension and gestational hypertension. In my opinion, the much more clinically relevant question concerns women with chronic hypertension, who have a long duration of treatment.
- the choice of high-level neonatal care as part of the composite endpoint. This aspect of the composite outcome drove the endpoint in terms of numbers, but it is unclear to me what its clinical relevance is. In my opinion, it is a poor surrogate for the neonatal outcomes we really care about.
What this evidence means for practice
This study does not establish a foundation for a change in clinical practice. At best, it supports the maternal safety of less-tight control of hypertension in pregnancy. That aspect of the trial may find its way into counseling of the patient.
–George Macones, MD
Share your thoughts on this article! Send your Letter to the Editor to rbarbieri@frontlinemedcom.com. Please include your name and the city and state in which you practice.
Does an unfavorable cervix preclude induction of labor at term in women who have gestational hypertension or mild preeclampsia?
The optimal management of gestational hypertension and mild preeclampsia at term has been a subject of great debate over the past decade. The controversy centers on the timing of delivery—induction of labor versus expectant management.
Proponents of immediate induction raise the valid concern that maternal disease may worsen if pregnancy is allowed to continue. Conversely, proponents of expectant management point to the possibility that the rate of cesarean delivery will be increased with immediate induction; they also cite concerns that neonatal morbidity may be increased with an early term delivery.
To shed light on this debate, investigators in the well-known HYPITAT trial randomly assigned 756 women who had gestational hypertension or mild preeclampsia at term to induction of labor (n = 377) or expectant management (n = 379). All women were carrying a singleton fetus that was 36 to 41 weeks old, with cephalic presentation. The main findings of the trial, published in Lancet, were that induction of labor produced fewer “high-risk situations” (relative risk [RR], 0.71; 95% confidence interval [CI], 0.59–0.86), with no increase in the risk of cesarean delivery (RR, 0.75; 95% CI, 0.55–1.04) or adverse neonatal outcomes (RR, 0.75; 95% CI, 0.45–1.26).1
Although these findings are important, one question lingered in the minds of many obstetricians: Should the choice between induction of labor and expectant management hinge on the favorability of the cervix?
That is the question addressed by Tajik and colleagues.
Zooming in on cervical status
In their secondary analysis from the HYPITAT trial, Tajik and colleagues reanalyzed the association between induction of labor and expectant management, focusing on the same outcomes (high-risk situations, cesarean delivery, adverse neonatal outcomes), but they stratified their data by cervical status. As stated above, their findings are surprising and seemingly counterintuitive:
- Among women who underwent immediate induction of labor, cervical length was not associated with a higher probability of high-risk situations
- The beneficial effect of induction of labor—in terms of reducing the rate of cesarean delivery—was greater among women who had an unfavorable cervix.
Strengths and limitations of the trial
Overall, this was a well-conducted secondary analysis that tackled an important issue. It featured 1) a robust dataset, with all variables of interest collected, and 2) a thoughtful approach to data analysis.
However, the analysis also raises a question: Is it possible that some of its negative findings (composite neonatal morbidity) are due to insufficient power? This is a question I ask whenever I encounter a secondary analysis of a randomized, controlled trial. The answer here: Possibly.
This study provides additional evidence that induction of labor is the optimal approach to gestational hypertension or mild preeclampsia in a pregnancy at 36 weeks or beyond—regardless of cervical status. I would expect clinicians to embrace the findings of the HYPITAT trial, including the secondary analysis, and incorporate this management strategy in their practice.
GEORGE MACONES, MD
We want to hear from you! Tell us what you think.
ON OBSTETRICS?
Is the rate of progress the same for induced and spontaneous labors?
William F. Rayburn, MD (November 2012)
Does maternal exposure to magnesium sulfate affect fetal heart-rate patterns?
John M. Thorp, Jr, MD (October 2012)
Is elective delivery at 37 weeks’ gestation safe in uncomplicated twin pregnancies?
Steven T. Chasen, MD (September 2012)
Does mediolateral episiotomy reduce the risk of anal sphincter injury in operative vaginal delivery?
Errol T. Norwitz, MD, PhD (August 2012)
Reference
1. Koopmans CM, Bijlenga D, Groen H, et al. HYPITAT Study Group. Induction of labour versus expectant monitoring for gestational hypertension or mild preeclampsia after 36 weeks’ gestation (HYPITAT): a multicentre, open-label randomised controlled trial. Lancet. 2009;374(9694):979-988.
The optimal management of gestational hypertension and mild preeclampsia at term has been a subject of great debate over the past decade. The controversy centers on the timing of delivery—induction of labor versus expectant management.
Proponents of immediate induction raise the valid concern that maternal disease may worsen if pregnancy is allowed to continue. Conversely, proponents of expectant management point to the possibility that the rate of cesarean delivery will be increased with immediate induction; they also cite concerns that neonatal morbidity may be increased with an early term delivery.
To shed light on this debate, investigators in the well-known HYPITAT trial randomly assigned 756 women who had gestational hypertension or mild preeclampsia at term to induction of labor (n = 377) or expectant management (n = 379). All women were carrying a singleton fetus that was 36 to 41 weeks old, with cephalic presentation. The main findings of the trial, published in Lancet, were that induction of labor produced fewer “high-risk situations” (relative risk [RR], 0.71; 95% confidence interval [CI], 0.59–0.86), with no increase in the risk of cesarean delivery (RR, 0.75; 95% CI, 0.55–1.04) or adverse neonatal outcomes (RR, 0.75; 95% CI, 0.45–1.26).1
Although these findings are important, one question lingered in the minds of many obstetricians: Should the choice between induction of labor and expectant management hinge on the favorability of the cervix?
That is the question addressed by Tajik and colleagues.
Zooming in on cervical status
In their secondary analysis from the HYPITAT trial, Tajik and colleagues reanalyzed the association between induction of labor and expectant management, focusing on the same outcomes (high-risk situations, cesarean delivery, adverse neonatal outcomes), but they stratified their data by cervical status. As stated above, their findings are surprising and seemingly counterintuitive:
- Among women who underwent immediate induction of labor, cervical length was not associated with a higher probability of high-risk situations
- The beneficial effect of induction of labor—in terms of reducing the rate of cesarean delivery—was greater among women who had an unfavorable cervix.
Strengths and limitations of the trial
Overall, this was a well-conducted secondary analysis that tackled an important issue. It featured 1) a robust dataset, with all variables of interest collected, and 2) a thoughtful approach to data analysis.
However, the analysis also raises a question: Is it possible that some of its negative findings (composite neonatal morbidity) are due to insufficient power? This is a question I ask whenever I encounter a secondary analysis of a randomized, controlled trial. The answer here: Possibly.
This study provides additional evidence that induction of labor is the optimal approach to gestational hypertension or mild preeclampsia in a pregnancy at 36 weeks or beyond—regardless of cervical status. I would expect clinicians to embrace the findings of the HYPITAT trial, including the secondary analysis, and incorporate this management strategy in their practice.
GEORGE MACONES, MD
We want to hear from you! Tell us what you think.
ON OBSTETRICS?
Is the rate of progress the same for induced and spontaneous labors?
William F. Rayburn, MD (November 2012)
Does maternal exposure to magnesium sulfate affect fetal heart-rate patterns?
John M. Thorp, Jr, MD (October 2012)
Is elective delivery at 37 weeks’ gestation safe in uncomplicated twin pregnancies?
Steven T. Chasen, MD (September 2012)
Does mediolateral episiotomy reduce the risk of anal sphincter injury in operative vaginal delivery?
Errol T. Norwitz, MD, PhD (August 2012)
The optimal management of gestational hypertension and mild preeclampsia at term has been a subject of great debate over the past decade. The controversy centers on the timing of delivery—induction of labor versus expectant management.
Proponents of immediate induction raise the valid concern that maternal disease may worsen if pregnancy is allowed to continue. Conversely, proponents of expectant management point to the possibility that the rate of cesarean delivery will be increased with immediate induction; they also cite concerns that neonatal morbidity may be increased with an early term delivery.
To shed light on this debate, investigators in the well-known HYPITAT trial randomly assigned 756 women who had gestational hypertension or mild preeclampsia at term to induction of labor (n = 377) or expectant management (n = 379). All women were carrying a singleton fetus that was 36 to 41 weeks old, with cephalic presentation. The main findings of the trial, published in Lancet, were that induction of labor produced fewer “high-risk situations” (relative risk [RR], 0.71; 95% confidence interval [CI], 0.59–0.86), with no increase in the risk of cesarean delivery (RR, 0.75; 95% CI, 0.55–1.04) or adverse neonatal outcomes (RR, 0.75; 95% CI, 0.45–1.26).1
Although these findings are important, one question lingered in the minds of many obstetricians: Should the choice between induction of labor and expectant management hinge on the favorability of the cervix?
That is the question addressed by Tajik and colleagues.
Zooming in on cervical status
In their secondary analysis from the HYPITAT trial, Tajik and colleagues reanalyzed the association between induction of labor and expectant management, focusing on the same outcomes (high-risk situations, cesarean delivery, adverse neonatal outcomes), but they stratified their data by cervical status. As stated above, their findings are surprising and seemingly counterintuitive:
- Among women who underwent immediate induction of labor, cervical length was not associated with a higher probability of high-risk situations
- The beneficial effect of induction of labor—in terms of reducing the rate of cesarean delivery—was greater among women who had an unfavorable cervix.
Strengths and limitations of the trial
Overall, this was a well-conducted secondary analysis that tackled an important issue. It featured 1) a robust dataset, with all variables of interest collected, and 2) a thoughtful approach to data analysis.
However, the analysis also raises a question: Is it possible that some of its negative findings (composite neonatal morbidity) are due to insufficient power? This is a question I ask whenever I encounter a secondary analysis of a randomized, controlled trial. The answer here: Possibly.
This study provides additional evidence that induction of labor is the optimal approach to gestational hypertension or mild preeclampsia in a pregnancy at 36 weeks or beyond—regardless of cervical status. I would expect clinicians to embrace the findings of the HYPITAT trial, including the secondary analysis, and incorporate this management strategy in their practice.
GEORGE MACONES, MD
We want to hear from you! Tell us what you think.
ON OBSTETRICS?
Is the rate of progress the same for induced and spontaneous labors?
William F. Rayburn, MD (November 2012)
Does maternal exposure to magnesium sulfate affect fetal heart-rate patterns?
John M. Thorp, Jr, MD (October 2012)
Is elective delivery at 37 weeks’ gestation safe in uncomplicated twin pregnancies?
Steven T. Chasen, MD (September 2012)
Does mediolateral episiotomy reduce the risk of anal sphincter injury in operative vaginal delivery?
Errol T. Norwitz, MD, PhD (August 2012)
Reference
1. Koopmans CM, Bijlenga D, Groen H, et al. HYPITAT Study Group. Induction of labour versus expectant monitoring for gestational hypertension or mild preeclampsia after 36 weeks’ gestation (HYPITAT): a multicentre, open-label randomised controlled trial. Lancet. 2009;374(9694):979-988.
Reference
1. Koopmans CM, Bijlenga D, Groen H, et al. HYPITAT Study Group. Induction of labour versus expectant monitoring for gestational hypertension or mild preeclampsia after 36 weeks’ gestation (HYPITAT): a multicentre, open-label randomised controlled trial. Lancet. 2009;374(9694):979-988.