Topic Resources
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Chronic hypertension: Blood pressure was high before the pregnancy.
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Gestational hypertension: Blood pressure became high for the first time after women had been pregnant for 20 weeks (usually after 37 weeks). This type of hypertension typically resolves within 6 weeks after delivery.
Preeclampsia
is another type of high blood pressure that develops during pregnancy.
It is accompanied by protein in the urine. Preeclampsia is diagnosed and
treated differently from other types of high blood pressure.
Women who have chronic hypertension are more likely to have
potentially serious problems during pregnancy. However, the following
problems are more likely to occur if either chronic or gestational
hypertension is present:
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Preeclampsia and/or eclampsia (seizures due to severe preeclampsia)
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The HELLP syndrome
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Worsening of high blood pressure
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A fetus that does not grow as much as expected (small for gestational age)
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Premature detachment of the placenta from the uterus (placental abruption)
The HELLP syndrome consists of hemolysis (the breakdown of red blood cells), elevated levels of liver enzymes (indicating liver damage), and a low platelet count, making blood less able to clot and increasing the risk of bleeding during and after labor.
During pregnancy, women with high blood pressure are monitored
closely to make sure blood pressure is well-controlled, the kidneys are
functioning normally, and the fetus is growing normally. However,
premature detachment of the placenta cannot be prevented or anticipated.
Often, a baby must be delivered early to prevent stillbirth or
complications due to severe high blood pressure (such as stroke) in the
woman.
Diagnosis
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Routine measurement of blood pressure
Blood pressure is measured routinely at prenatal visits.
Usually if severe hypertension occurs for the first time in
pregnant women, doctors do tests to rule out other causes of
hypertension.
Treatment
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For mild to moderate high blood pressure, reduced activity and, if needed, antihypertensive drugs
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For more severe high blood pressure, antihypertensive drugs
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Avoidance of certain antihypertensive drugs
Drugs may or may not be used, depending on how high blood pressure is and how well the kidneys are functioning. Use and choice of drugs to treat chronic and gestational hypertension are similar. However, gestational hypertension often occurs late in pregnancy and does not require treatment with drugs.
For mild to moderate high blood pressure (140/90 to
159/109 millimeters of mercury [mm Hg]), treatment depends on many
factors. Doctors may recommend reducing physical activity to possibly
help lower blood pressure. If reduced activity does not lower blood
pressure, many experts recommend treatment with antihypertensive drugs.
Whether the benefits of these drugs outweigh the risks is unclear.
However, if the kidneys are not functioning normally, drugs are needed.
If high blood pressure is not controlled well, the kidneys may be
damaged further.
For severe high blood pressure (160/110 mm Hg or higher), treatment with antihypertensive drugs is recommended (see table Antihypertensive Drugs). Treatment can reduce the risk of stroke and other complications due to high blood pressure.
For very high blood pressure (180/110 mm Hg or higher),
women are evaluated immediately because risk of complications for women
and/or the fetus is high. If women wish to continue the pregnancy
despite the risk, they often require several antihypertensive drugs.
They may be hospitalized toward the end of the pregnancy. If their
condition worsens, doctors may recommend ending the pregnancy.
Women are taught to check their blood pressure at home. Doctors
periodically do tests to determine how well the kidneys and liver are
functioning and do ultrasonography to determine how well the fetus is
growing.
If pregnant women have moderately high to very high blood
pressure, the baby is typically delivered at 37 to 39 weeks. It is
delivered earlier if the fetus is growing slowly, the fetus is having
problems, or the woman has severe preeclampsia.
Antihypertensive drugs
Most antihypertensive drugs used to treat high blood pressure can be used safely during pregnancy. They include
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Methyldopa
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Beta-blockers (most commonly, labetalol)
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Calcium channel blockers (such as nifedipine)
However, angiotensin-converting enzyme (ACE) inhibitors are
stopped during pregnancy, particularly during the last two trimesters.
These drugs can cause birth defects of the urinary tract in the fetus.
As a result, the baby may die shortly after birth.
Angiotensin II receptor blockers are stopped because they
increase the risk of kidney, lung, and skeletal problems and death in
the fetus.
Aldosterone antagonists (spironolactone and eplerenone) are also stopped because they can cause a male fetus to develop feminine characteristics.
Thiazide diuretics are usually stopped because they can cause low
potassium levels in the fetus. However, if other drugs are ineffective
or have intolerable side effects, women with chronic hypertension may be
given thiazide diuretics (such as hydrochlorothiazide) during pregnancy.
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