Pharmacy Clinic
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Hypertension in Pregnancy
High blood pressure or hypertension during pregnancy has been one of the leading
causes of prenatal mortality (death of mother, fetus or newborn). Pre-eclampsia
(or toxemia, as it was historically called) is the hypertensive disease that occurs
only in pregnancy. Almost 10 percent of pregnancies are complicated by pre-
eclampsia.
Systolic and diastolic blood pressure decline in the first and second trimester of a
normal pregnancy, only in the third trimester blood pressure return to normal or
elevated.
Hypertension during pregnancy is defined as an increase in systolic blood pressure
of 30 mm Hg or an increase in the diastolic blood pressure of 15 mm Hg over the
base line of pregnant hypertension.
Hypertension during pregnancy divided into four categories:
*Chronic hypertension
*Preeclampsia-eclampsia
*Preeclampsia superimposed on chronic hypertension
*Transient Hypertension
This classification is done to differentiate between women with chronic
hypertension from those with pregnancy induced or pregnancy specific
hypertension.
Preeclampsia is the presence of hypertension with proteinuria, edema or both
occur after week 20 of pregnancy (proteinuria of 30mg/dl in a random urine
selection). If Preeclampsia happened in women with chronic hypertension, it may
be termed Preeclampsia superimposed on chronic hypertension. Preeclampsia
ranged from mild to severe and can lead to the development of Preeclampsia
variant in which a women exhibits hemolytic anemia, elevated liver enzymes, and
has decreased platelet count or to eclampsia which may be defined as
convulsions or seizures that occur in a patient with Preeclampsia. All these cases
required hospitalization, antihypertensive therapy, may be anticonvulsant
therapy.
Transient hypertension is the increase in blood pressure during pregnancy with
out signs and symptoms of Preeclampsia woman who did not have pre-existing
hypertension.
Definition:
Pre-eclampsia is an illness arising only in pregnancy, which can affect both the
mother and her unborn child. It affects as many as one in ten of all pregnancies
making it the most common serious antenatal complication.
It can develop at any time in the second half of pregnancy. In the mother the
condition causes a number of symptomless disturbances including raised blood
pressure and protein in the urine. The unborn baby may grow more slowly than
normal or suffer potentially dangerous oxygen deficiency.
Pre-eclampsia occurs more often among some groups of women. At higher risk for
the disease are women who:
•are under 20 years old, with a first pregnancy
•are over 35 years old, with a first pregnancy
•have chronic, or "essential" hypertension
•had hypertension in a previous pregnancy, other than the first
•have multiple gestation (twins, etc.)
•have diabetes
Signs AND Symptoms
Pre-eclampsia has been called the great imitator (تقليدي) because its symptoms are
often much like many other diseases. Characteristic signs and symptoms occur
after the 20th week of pregnancy and include:
1.High Blood Pressure: BP of at least 140 over 90 is considered hypertension (160
over 110 is "severe"). If the woman's normal (pre-pregnant or very early
pregnancy) blood pressure is not known, it's very hard to distinguish pre-
eclampsia from chronic hypertension. Pre-eclampsia is more dangerous to the
mother and baby. About 20 percent of women with chronic hypertension will
develop pre-eclampsia too.
2.Swelling, or "edema": This is a common sign and may go along with a rapid
weight gain. Swelling is a confusing symptom. It is normal to have some swelling
of the feet or ankles, especially late in pregnancy and some women with pre-
eclampsia will have no edema. Swelling is not a reliable symptom of pre-
eclampsia.
3.Protein in the urine: The presence of protein in the urine is considered to be an
important factor for making the diagnosis of pre-eclampsia. The disease causes
damage to the filtering function of the kidneys (repairs itself after delivery),
which allows protein to "spill" into the urine. Even though it is a reliable sign of
pre-eclampsia, protein in the urine very often does not occur until the disease has
progressed to a later stage.
The majority of women with pre-eclampsia feel perfectly well. It can only be
detected by the routine screening tests carried out at ante-natal visits.
A combination of any two of the following is suggestive of pre-eclampsia:
Other symptoms which may arise include upper abdominal pain and vomiting,
severe headache and visual disturbances. These symptoms can indicate the
disease has reached an advanced stage.
Pre-eclampsia can develop very quickly. Be alert to these symptoms.
Pre-eclampsia differs from a normal pregnancy in the following:
Many adjustments in the mother's body happen during a pregnancy to allow the
fetus to grow normally, and to help the mother's systems handle the additional
"work" required by the pregnancy. Some adjustments do not happen the same
way in the woman with pre-eclampsia.
1.In a normal pregnancy the fluid part of the mother's blood increases
dramatically, resulting in a 35-50% increase in the total volume. This helps serve
the added needs of the uterus and placenta, among other functions. In the
woman with pre-eclampsia, the blood volume increases only a small amount or
not at all.
2.The "resistance", or stiffness of the blood vessels throughout the mother's body
normally decreases, allowing free flow of blood to the placenta and uterus.
Pregnancy hormones and changes in the blood vessel regulating mechanisms
"relax" the vessel walls. With pre-eclampsia, instead of relaxing, the blood
vessels spasm.
3.Normally, the pregnant woman's blood pressure drops a little in mid-pregnancy,
partly because of the increase in volume of blood, and partly due to the relaxing
of the blood vessels. With pre-eclampsia, the blood pressure does not drop in
mid-pregnancy, and the blood pressure increases in the last weeks.
4.With the increase in blood volume and relaxed vessels, the normal pregnant
woman gets extra blood flow to the uterus, kidneys, liver and other organs. In the
woman with pre-eclampsia, the vessels are in spasm, and this blood flow is
decreased instead. The spasm in the small vessels of the body is believed to
cause the organ damage that happens with the disease. Kidney damage is one
example - protein in the urine is what results from the damage. Other organs,
especially the liver can also be damaged. Except in the most severe cases, organ
damage heals by itself after delivery of the baby.
5.In the normal pregnancy, blood clotting is affected very slightly. With severe
pre-eclampsia, platelets (clotting factors in the blood) can be very low, and the
blood does not clot normally. This results in a life threatening risk of internal
bleeding.
Etiology of Pre-eclampsia
Genetic factors are probably involved since women whose mothers and sisters
have suffered pre-eclampsia are more likely to get it themselves.
What is known is that pre-eclampsia originates in the placenta. The placenta
needs a large and efficient blood supply from the mother to sustain the growing
baby. In pre-eclampsia the placenta runs short of blood either because its
demands are unusually high - as with twins - or because the arteries in the womb
(الرحم) did not enlarge as they should have done when the placenta was being
formed in the first half of pregnancy. This shortage of blood has serious
consequences for mother and baby.
It is not known what causes this disease. A current theory holds that pre-
eclampsia is a process that begins early in the pregnancy as the developing
embryo implants in the wall of the uterus to form the placenta. Normally, a
complex series of events causes changes in the blood vessels of the uterus which
allow them to remain relaxed to nourish the growing baby. In pre-eclampsia, this
process does not occur or is incomplete very early. The chemical imbalances that
result are believed to lead to the spasm and "stiffness" of the blood vessels
throughout the mother's body. It is this spasm that causes the complications of
pre-eclampsia - namely organ damage.
The etiology of Preeclampsia is may be associated with increased maternal
vasoconstrictor tone, prostaglandin imbalance and immunological problem during
pregnancy.
Increased Vasoconstrictor Tone
Women with Preeclampsia appear to have markedly increased vasoconstrictor
tone and this increase in the response to vasoconstrictors can be detected before
the clinical development of prteeclampsia; thus, Preeclampsia may be a chronic
problem during pregnancy that persist when the fetus is delivered.
Prostaglandin imbalance
The development of Preeclampsia may reflect a deficiency of certain
prostaglandins that can occur as a result of prostaglandin precursor deficiency,
defective prostaglandin activity, or lowered prostaglandin synthetase enzyme
action.
The imbalance in the process of enoperoxides conversion to prostaglandins E2
and F2, prostacycline, thromboxane occurs in woman with Preeclampsia. The
reduction in the vasodilator prostaglandins induce blood vessel constriction. Also
prostacycline is a potent vasodilator and oppose platelet aggregation process in
the pregnant woman.
Complication of Preeclampsia in the mother and her baby
Damage to organs, such as the kidney and liver, and swelling or fluid in the lungs
are dangerous complications of pre-eclampsia. These problems are caused by the
decreased flow of blood and vessels in spasm. Since the uterus also gets less
blood flow, often the placenta is damaged. The baby may not grow well, and may
be overly stressed during labor.
Many women with pre-eclampsia will deliver an essentially healthy baby. Some
women will experience only an anxious nurse-midwife or doctor, and maybe
delivery a week or so earlier. Some women, however, progress rapidly to more
severe forms of the disease.
Two very serious consequences are:
1.Eclampsia is when the mother has convulsions. Serious complications such as
brain injury as a result of the convulsion are uncommon but do occur. The fetus is
deprived (يستنفذ) of oxygen during the convulsion, and damage or separation of the
placenta can occur. Preventing eclampsia is one of the major goals of treating
pre-eclampsia.
2.HELLP Syndrome stands for hemolysis (destruction of red blood cells), elevated
liver enzymes (indicating liver damage), and low platelets (internal bleeding risk).
HELLP Syndrome is a life threatening condition for both mother and fetus.
Prevention of Preeclampsia:
The search for something to predict or prevent pre-eclampsia has continued since
the time of Hippocrates. Most suggestions have not helped much. Considering the
current theory of early placenta development problems, it seems unlikely that
prevention will be a simple matter.
Among the suggestions, several have involved dietary changes. Calcium intake
appears to play some role in reducing pre-eclampsia. Adequate amounts of
calcium (1,200 - 1,500 mg per day) can be obtained from a balanced diet which
includes 3 to 4 servings of milk or dairy products daily. If the diet is not
adequate, a supplement may be recommended.
Low dose aspirin therapy is being studied as one possible way to prevent the
chemical imbalances at the placenta, which are believed to be a cause of pre-
eclampsia. Obstetricians and Gynecologists recommends that aspirin be used only
in women at very high risk for pre-eclampsia. There isn't enough evidence of its
benefits to recommend it for all pregnant women.
Although the disease may not be prevented, the serious complications from pre-
eclampsia can be. Women can be aware of the danger signs of pre-eclampsia, and
report them promptly to their care provider or clinic
There is no hard evidence that pre-eclampsia can be caused or prevented by what
the mother eats, or whether the mother smokes or drinks, how hard she works or
how much rest she has.
The best plan is to have regular antenatal check-ups, which can detect the
earliest signs of pre-eclampsia and other complications.
Take an active interest in your ante-natal checks, never miss an appointment,
and make sure you have your blood pressure and urine checked regularly. Of
course, any worrying signs or symptoms should be reported to your doctor.
Vitamins C, E and A for Eclampsia
Research suggests that vitamin C and possibly vitamin E and betacarotene may
be instrumental in preventing Preeclampsia. When researchers measured the
levels of these antioxidants in the blood of 30 women with Preeclampsia and 44
women without, they found those with Preeclampsia had much lower levels.
The body relies on vitamin C to fend off the free radicals that injure blood vessels
in the uterus and placenta and trigger the high blood pressure and swollen
tissues that accompany the disease. Antioxidants may be more important in
prevention than in treatment; adequate levels going into pregnancy could keep
free radicals a way.
Treatment of Preeclampsia
Delivery of the placenta and baby is the only known treatment. When the disease
occurs in the last weeks of pregnancy, bed rest and observation for worsening of
pre-eclampsia may be attempted, but often labor must be induced, or in severe
cases, cesarean birth performed.
Generally, the earlier signs of the disease are seen, the more severe it is likely to
become. Even with mild pre-eclampsia near full term, however, a significant
decrease in placental blood flow has already occurred, and delivery is
recommended.
Treatment should first involve non-pharmacological means (restricted activity,
nutritional diet.). If that approach fails, then drug therapy may be necessary. The
most commonly used drugs to treat hypertension in pregnancy are the beta-
blockers, calcium channel blockers, methyldopa, and hydralazine.
Beta-blockers are very effective and seem to be safe. If a beta-blocker is to be
used, the newer cardioselective (beta-1) agents should be considered. This
reduces the likelihood of hypoglycemia and respiratory problems caused by beta-2
blockade. Some sources state that beta-blockers should not be used for the entire
pregnancy because use during the first and second trimester is associated with
intrauterine growth retardation. Beta-blockers may cause fetal bradycardia. The
most commonly used agent is labetalol, however the use of metoprolol is
increasing.
The calcium channel blockers have not been used extensively in pregnancy, but
seem to be safe and effective. The Dihydropyridine (i.e. nifedipine) class of
calcium channel blockers has been the most frequently used. They are associated
with a low incidence of maternal adverse effects.
Methyldopa is the golden standard of treatment. It has been extensively studied
and is proven safe to the fetus. However, it is not tolerated as well as beta-
blockers or calcium channel blockers. Methyldopa is not as efficient at lowering
blood pressure as the newer agents.
Hydralazine is another golden standard of treatment. It also is basically proven
safe to the fetus but is associated with a high maternal adverse effect profile.
Hydralazine can lower maternal blood pressure rapidly which can reduce
intrauterine perfusion.
ACE inhibitors and diuretics should not be used during pregnancy. ACE inhibitors
can cause renal failure and death to the fetus. Diuretics should not be used
because they can cause depletion of fluid volume and electrolyte deficiencies
which can be harmful to the fetus.
causes of prenatal mortality (death of mother, fetus or newborn). Pre-eclampsia
(or toxemia, as it was historically called) is the hypertensive disease that occurs
only in pregnancy. Almost 10 percent of pregnancies are complicated by pre-
eclampsia.
Systolic and diastolic blood pressure decline in the first and second trimester of a
normal pregnancy, only in the third trimester blood pressure return to normal or
elevated.
Hypertension during pregnancy is defined as an increase in systolic blood pressure
of 30 mm Hg or an increase in the diastolic blood pressure of 15 mm Hg over the
base line of pregnant hypertension.
Hypertension during pregnancy divided into four categories:
*Chronic hypertension
*Preeclampsia-eclampsia
*Preeclampsia superimposed on chronic hypertension
*Transient Hypertension
This classification is done to differentiate between women with chronic
hypertension from those with pregnancy induced or pregnancy specific
hypertension.
Preeclampsia is the presence of hypertension with proteinuria, edema or both
occur after week 20 of pregnancy (proteinuria of 30mg/dl in a random urine
selection). If Preeclampsia happened in women with chronic hypertension, it may
be termed Preeclampsia superimposed on chronic hypertension. Preeclampsia
ranged from mild to severe and can lead to the development of Preeclampsia
variant in which a women exhibits hemolytic anemia, elevated liver enzymes, and
has decreased platelet count or to eclampsia which may be defined as
convulsions or seizures that occur in a patient with Preeclampsia. All these cases
required hospitalization, antihypertensive therapy, may be anticonvulsant
therapy.
Transient hypertension is the increase in blood pressure during pregnancy with
out signs and symptoms of Preeclampsia woman who did not have pre-existing
hypertension.
Definition:
Pre-eclampsia is an illness arising only in pregnancy, which can affect both the
mother and her unborn child. It affects as many as one in ten of all pregnancies
making it the most common serious antenatal complication.
It can develop at any time in the second half of pregnancy. In the mother the
condition causes a number of symptomless disturbances including raised blood
pressure and protein in the urine. The unborn baby may grow more slowly than
normal or suffer potentially dangerous oxygen deficiency.
Pre-eclampsia occurs more often among some groups of women. At higher risk for
the disease are women who:
•are under 20 years old, with a first pregnancy
•are over 35 years old, with a first pregnancy
•have chronic, or "essential" hypertension
•had hypertension in a previous pregnancy, other than the first
•have multiple gestation (twins, etc.)
•have diabetes
Signs AND Symptoms
Pre-eclampsia has been called the great imitator (تقليدي) because its symptoms are
often much like many other diseases. Characteristic signs and symptoms occur
after the 20th week of pregnancy and include:
1.High Blood Pressure: BP of at least 140 over 90 is considered hypertension (160
over 110 is "severe"). If the woman's normal (pre-pregnant or very early
pregnancy) blood pressure is not known, it's very hard to distinguish pre-
eclampsia from chronic hypertension. Pre-eclampsia is more dangerous to the
mother and baby. About 20 percent of women with chronic hypertension will
develop pre-eclampsia too.
2.Swelling, or "edema": This is a common sign and may go along with a rapid
weight gain. Swelling is a confusing symptom. It is normal to have some swelling
of the feet or ankles, especially late in pregnancy and some women with pre-
eclampsia will have no edema. Swelling is not a reliable symptom of pre-
eclampsia.
3.Protein in the urine: The presence of protein in the urine is considered to be an
important factor for making the diagnosis of pre-eclampsia. The disease causes
damage to the filtering function of the kidneys (repairs itself after delivery),
which allows protein to "spill" into the urine. Even though it is a reliable sign of
pre-eclampsia, protein in the urine very often does not occur until the disease has
progressed to a later stage.
The majority of women with pre-eclampsia feel perfectly well. It can only be
detected by the routine screening tests carried out at ante-natal visits.
A combination of any two of the following is suggestive of pre-eclampsia:
Other symptoms which may arise include upper abdominal pain and vomiting,
severe headache and visual disturbances. These symptoms can indicate the
disease has reached an advanced stage.
Pre-eclampsia can develop very quickly. Be alert to these symptoms.
Pre-eclampsia differs from a normal pregnancy in the following:
Many adjustments in the mother's body happen during a pregnancy to allow the
fetus to grow normally, and to help the mother's systems handle the additional
"work" required by the pregnancy. Some adjustments do not happen the same
way in the woman with pre-eclampsia.
1.In a normal pregnancy the fluid part of the mother's blood increases
dramatically, resulting in a 35-50% increase in the total volume. This helps serve
the added needs of the uterus and placenta, among other functions. In the
woman with pre-eclampsia, the blood volume increases only a small amount or
not at all.
2.The "resistance", or stiffness of the blood vessels throughout the mother's body
normally decreases, allowing free flow of blood to the placenta and uterus.
Pregnancy hormones and changes in the blood vessel regulating mechanisms
"relax" the vessel walls. With pre-eclampsia, instead of relaxing, the blood
vessels spasm.
3.Normally, the pregnant woman's blood pressure drops a little in mid-pregnancy,
partly because of the increase in volume of blood, and partly due to the relaxing
of the blood vessels. With pre-eclampsia, the blood pressure does not drop in
mid-pregnancy, and the blood pressure increases in the last weeks.
4.With the increase in blood volume and relaxed vessels, the normal pregnant
woman gets extra blood flow to the uterus, kidneys, liver and other organs. In the
woman with pre-eclampsia, the vessels are in spasm, and this blood flow is
decreased instead. The spasm in the small vessels of the body is believed to
cause the organ damage that happens with the disease. Kidney damage is one
example - protein in the urine is what results from the damage. Other organs,
especially the liver can also be damaged. Except in the most severe cases, organ
damage heals by itself after delivery of the baby.
5.In the normal pregnancy, blood clotting is affected very slightly. With severe
pre-eclampsia, platelets (clotting factors in the blood) can be very low, and the
blood does not clot normally. This results in a life threatening risk of internal
bleeding.
Etiology of Pre-eclampsia
Genetic factors are probably involved since women whose mothers and sisters
have suffered pre-eclampsia are more likely to get it themselves.
What is known is that pre-eclampsia originates in the placenta. The placenta
needs a large and efficient blood supply from the mother to sustain the growing
baby. In pre-eclampsia the placenta runs short of blood either because its
demands are unusually high - as with twins - or because the arteries in the womb
(الرحم) did not enlarge as they should have done when the placenta was being
formed in the first half of pregnancy. This shortage of blood has serious
consequences for mother and baby.
It is not known what causes this disease. A current theory holds that pre-
eclampsia is a process that begins early in the pregnancy as the developing
embryo implants in the wall of the uterus to form the placenta. Normally, a
complex series of events causes changes in the blood vessels of the uterus which
allow them to remain relaxed to nourish the growing baby. In pre-eclampsia, this
process does not occur or is incomplete very early. The chemical imbalances that
result are believed to lead to the spasm and "stiffness" of the blood vessels
throughout the mother's body. It is this spasm that causes the complications of
pre-eclampsia - namely organ damage.
The etiology of Preeclampsia is may be associated with increased maternal
vasoconstrictor tone, prostaglandin imbalance and immunological problem during
pregnancy.
Increased Vasoconstrictor Tone
Women with Preeclampsia appear to have markedly increased vasoconstrictor
tone and this increase in the response to vasoconstrictors can be detected before
the clinical development of prteeclampsia; thus, Preeclampsia may be a chronic
problem during pregnancy that persist when the fetus is delivered.
Prostaglandin imbalance
The development of Preeclampsia may reflect a deficiency of certain
prostaglandins that can occur as a result of prostaglandin precursor deficiency,
defective prostaglandin activity, or lowered prostaglandin synthetase enzyme
action.
The imbalance in the process of enoperoxides conversion to prostaglandins E2
and F2, prostacycline, thromboxane occurs in woman with Preeclampsia. The
reduction in the vasodilator prostaglandins induce blood vessel constriction. Also
prostacycline is a potent vasodilator and oppose platelet aggregation process in
the pregnant woman.
Complication of Preeclampsia in the mother and her baby
Damage to organs, such as the kidney and liver, and swelling or fluid in the lungs
are dangerous complications of pre-eclampsia. These problems are caused by the
decreased flow of blood and vessels in spasm. Since the uterus also gets less
blood flow, often the placenta is damaged. The baby may not grow well, and may
be overly stressed during labor.
Many women with pre-eclampsia will deliver an essentially healthy baby. Some
women will experience only an anxious nurse-midwife or doctor, and maybe
delivery a week or so earlier. Some women, however, progress rapidly to more
severe forms of the disease.
Two very serious consequences are:
1.Eclampsia is when the mother has convulsions. Serious complications such as
brain injury as a result of the convulsion are uncommon but do occur. The fetus is
deprived (يستنفذ) of oxygen during the convulsion, and damage or separation of the
placenta can occur. Preventing eclampsia is one of the major goals of treating
pre-eclampsia.
2.HELLP Syndrome stands for hemolysis (destruction of red blood cells), elevated
liver enzymes (indicating liver damage), and low platelets (internal bleeding risk).
HELLP Syndrome is a life threatening condition for both mother and fetus.
Prevention of Preeclampsia:
The search for something to predict or prevent pre-eclampsia has continued since
the time of Hippocrates. Most suggestions have not helped much. Considering the
current theory of early placenta development problems, it seems unlikely that
prevention will be a simple matter.
Among the suggestions, several have involved dietary changes. Calcium intake
appears to play some role in reducing pre-eclampsia. Adequate amounts of
calcium (1,200 - 1,500 mg per day) can be obtained from a balanced diet which
includes 3 to 4 servings of milk or dairy products daily. If the diet is not
adequate, a supplement may be recommended.
Low dose aspirin therapy is being studied as one possible way to prevent the
chemical imbalances at the placenta, which are believed to be a cause of pre-
eclampsia. Obstetricians and Gynecologists recommends that aspirin be used only
in women at very high risk for pre-eclampsia. There isn't enough evidence of its
benefits to recommend it for all pregnant women.
Although the disease may not be prevented, the serious complications from pre-
eclampsia can be. Women can be aware of the danger signs of pre-eclampsia, and
report them promptly to their care provider or clinic
There is no hard evidence that pre-eclampsia can be caused or prevented by what
the mother eats, or whether the mother smokes or drinks, how hard she works or
how much rest she has.
The best plan is to have regular antenatal check-ups, which can detect the
earliest signs of pre-eclampsia and other complications.
Take an active interest in your ante-natal checks, never miss an appointment,
and make sure you have your blood pressure and urine checked regularly. Of
course, any worrying signs or symptoms should be reported to your doctor.
Vitamins C, E and A for Eclampsia
Research suggests that vitamin C and possibly vitamin E and betacarotene may
be instrumental in preventing Preeclampsia. When researchers measured the
levels of these antioxidants in the blood of 30 women with Preeclampsia and 44
women without, they found those with Preeclampsia had much lower levels.
The body relies on vitamin C to fend off the free radicals that injure blood vessels
in the uterus and placenta and trigger the high blood pressure and swollen
tissues that accompany the disease. Antioxidants may be more important in
prevention than in treatment; adequate levels going into pregnancy could keep
free radicals a way.
Treatment of Preeclampsia
Delivery of the placenta and baby is the only known treatment. When the disease
occurs in the last weeks of pregnancy, bed rest and observation for worsening of
pre-eclampsia may be attempted, but often labor must be induced, or in severe
cases, cesarean birth performed.
Generally, the earlier signs of the disease are seen, the more severe it is likely to
become. Even with mild pre-eclampsia near full term, however, a significant
decrease in placental blood flow has already occurred, and delivery is
recommended.
Treatment should first involve non-pharmacological means (restricted activity,
nutritional diet.). If that approach fails, then drug therapy may be necessary. The
most commonly used drugs to treat hypertension in pregnancy are the beta-
blockers, calcium channel blockers, methyldopa, and hydralazine.
Beta-blockers are very effective and seem to be safe. If a beta-blocker is to be
used, the newer cardioselective (beta-1) agents should be considered. This
reduces the likelihood of hypoglycemia and respiratory problems caused by beta-2
blockade. Some sources state that beta-blockers should not be used for the entire
pregnancy because use during the first and second trimester is associated with
intrauterine growth retardation. Beta-blockers may cause fetal bradycardia. The
most commonly used agent is labetalol, however the use of metoprolol is
increasing.
The calcium channel blockers have not been used extensively in pregnancy, but
seem to be safe and effective. The Dihydropyridine (i.e. nifedipine) class of
calcium channel blockers has been the most frequently used. They are associated
with a low incidence of maternal adverse effects.
Methyldopa is the golden standard of treatment. It has been extensively studied
and is proven safe to the fetus. However, it is not tolerated as well as beta-
blockers or calcium channel blockers. Methyldopa is not as efficient at lowering
blood pressure as the newer agents.
Hydralazine is another golden standard of treatment. It also is basically proven
safe to the fetus but is associated with a high maternal adverse effect profile.
Hydralazine can lower maternal blood pressure rapidly which can reduce
intrauterine perfusion.
ACE inhibitors and diuretics should not be used during pregnancy. ACE inhibitors
can cause renal failure and death to the fetus. Diuretics should not be used
because they can cause depletion of fluid volume and electrolyte deficiencies
which can be harmful to the fetus.