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IN THE NAME OF GOD
Management of hypertension in
pregnant women
Atefe Vafaei
95/5/10
INTRODUCTION :
●Preeclampsia: new onset of hypertension and either proteinuria or end- •
organ dysfunction most often after 20 weeks of gestation in a previously
normotensive woman.
●Chronic (preexisting) hypertension –systolic pressure ≥140 mmHg •
and/or diastolic pressure ≥90 mmHg that antedates pregnancy, is present
before the 20th week of pregnancy, or persists longer than 12 weeks
postpartum.
●Preeclampsia-eclampsia superimposed upon chronic hypertension –a •
woman with chronic hypertension develops worsening hypertension with
new onset proteinuria or other features of preeclampsia (eg, elevated liver
enzymes, low platelet count).
●Gestational hypertension –elevated blood pressure first detected after •
20 weeks of gestation in the absence of proteinuria or other diagnostic
features of preeclampsia. Over time, some patients with gestational
hypertension will develop proteinuria or end-organ dysfunction
characteristic of preeclampsia and be considered preeclamptic, while
others will be diagnosed with preexisting hypertension because of
persistent blood pressure elevation postpartum.
GENERAL APPROACH — The decision to treat hypertension •
during pregnancy should consider the risks and benefits for
both mother and fetus. The level of blood pressure is the
most important factor: Treatment of severe hypertension
(systolic BP ≥160 mmHg and/or diastolic BP ≥110 mmHg) is
always recommended because it is believed to reduce the risk
of maternal stroke.
The decision to use antihypertensive therapy in women with •
mild (systolic 140 to 150 mmHg, diastolic 90 to 100 mmHg) to
moderate (systolic 150 to 159 mmHg, diastolic 100 to 109
mmHg) hypertension and no comorbidities is less clear.
Antihypertensive therapy — •
All antihypertensive drugs cross the placenta. •
women with chronic hypertension, either
treated or untreated, are at increased risk of
congenital malformations, particularly cardiac
malformations, compared with normotensive
women.
Options — The following drugs are effective
antihypertensive agents with an acceptable safety
profile in pregnancy. The choice of drug depends on
the acuity and severity of hypertension and whether
or not parenteral or oral therapy is used; these
factors are discussed below.
Methyldopa — long-term safety for the fetus , a mild
antihypertensive agent and has a slow onset of action (three
to six hours). Many women will not achieve blood pressure
goals on this oral agent or are bothered by its sedative effect
at high doses.
Beta-blockers —the risk of congenital malformations associated
with first trimester oral beta-blocker exposure compared with
no exposure, there was no overall increase in major
congenital malformations (OR 0.90, 95% CI 0.91-1.10) .
Beta-blockers
Labetalol: both alpha- and beta-adrenergic blocking activity,
rapid onset of action than methyldopa (within two hours
versus three to six hours), associated with maternal
hepatotoxicity, which although rare, is important to recognize
as it may be confused with the elevated liver enzymes of the
HELLP (Hemolysis, Elevated Liver enzymes, and Low Platelet
count) syndrome. Most cases are reversible, but fatalities
have been reported(related to the duration of therapy in
chronic hypertension and differences in baseline
characteristics of the mothers ). , pindolol and the long-acting
form of metoprolol are acceptable alternative agents .
The safety of beta-adrenergic blockers is somewhat controversial
due to reports of premature labor, fetal growth restriction,
and neonatal apnea, bradycardia, and hypoglycemia .
Furthermore, myometrial relaxation of the gravid uterus is a
beta2-receptor-mediated process, and nonselective betaadrenergic blockers (such as propranolol) may counteract the
effect of beta2 stimulation. Beta-adrenergic blockers that lack
alpha-blocking properties (eg, atenolol) have been associated
with lower placental and fetal weight at delivery when used
early in pregnancy, and are generally avoided if an effective
drug with a better safety profile is available .
Calcium channel blockers —nifedipine ,amlodipine,
Nondihydropyridine calcium antagonists such as verapamiland
diltiazem.
We caution against the use of immediate release oral nifedipine,
although an American College of Obstetricians and Gynecologists
committee opinion endorsed its use as an option for emergent
treatment of acute, severe hypertension in pregnancy or
postpartum (other options were sustained release nifedipine,
labetalol, and hydralazine). In most cases use of immediate release
nifedipine will be safe and well tolerated; however, there is a small
risk of an acute, precipitous fall in blood pressure, which may result
in a reduction in uteroplacental perfusion and headache.
Hydralazine —intravenus of that is used for the •
acute treatment of severe hypertension. Hydralazine
can also be taken orally; however, it causes reflex
tachycardia and fluid retention, which limit its
usefulness in pregnancy.
Thiazide diuretics —these agents can be continued in
women with chronic hypertension who were taking
them prior to pregnancy. Diuretics are not generally
used in women with preeclampsia unless pulmonary
edema has developed.
Clonidine —an effective drug for treatment of mild
hypertension in pregnancy . However, it has
bothersome side effects and the possibility of
rebound hypertension if it is stopped suddenly, so
other agents are preferred.
Because clonidine is available as a transdermal patch,
it is particularly useful for patients who cannot take
an oral antihypertensive drug.
ACE inhibitors, ARBs, direct renin inhibitors —
contraindicated at all stages of pregnancy.
renal abnormalities when maternal exposure has been
in the latter half of pregnancy, and first trimester
exposure has been associated with fetal cardiac
abnormalities.
it is best to avoid initiating these drugs during
pregnancy and to discontinue these agents in women
planning pregnancy and switch to another agent.
Nitroprusside — Limited clinical experience pregnancies
and the possibility of fetal cyanide poisoning have restricted
the use of nitroprusside in pregnancy.
•
Activity —
Recommendations for level of activity should be
individualized; for example, a woman with stable
chronic hypertension early in pregnancy is unlikely to
benefit from bedrest, while a woman with newly
diagnosed preeclampsia in the third trimester should
be advised to limit activity if she is being managed as
an outpatient.
Diet — A normal diet without significant salt restriction
is generally advised, as salt restriction may induce
low intravascular volume.
MANAGEMENT OF COMMON HYPERTENSIVE
DISORDERS DURING PREGNANCY
1. Preeclampsia:
The definitive treatment of preeclampsia is delivery,
which is always beneficial for the mother.
However, delivery may not be beneficial for the fetus if
it is born preterm. Although the fetus is at increased
risk of intrauterine growth restriction and stillbirth in
the preeclamptic environment, conservative
management, including antihypertensive therapy,
may be pursued in selected cases to gain fetal
maturity.
Indications for antihypertensive therapy —
We do not prescribe antihypertensive therapy for mild
hypertension, which we define as blood pressures
consistently less than 150/100 mmHg. The benefit of
antihypertensive therapy in pregnant women with
mild hypertension is a reduction in risk of developing
severe hypertension , which may not be sufficient to
warrant exposing the fetus to the potential adverse
effects from these drugs .
Severe hypertension should be treated to prevent maternal
vascular complications.
We initiate antihypertensive therapy in adult women at
systolic pressures ≥150 mmHg or diastolic blood
pressures ≥100 mmHg. We may initiate treatment earlier
in women with signs of cardiac decompensation or
cerebral symptoms (eg, severe headache, visual
disturbances, chest discomfort, shortness of breath,
confusion) and in younger women whose baseline blood
pressures were low .
then women with preeclampsia may be more susceptible to
the neurologic features of severe disease at lower blood
pressures (eg, ≥150 mmHg systolic).
Choice of drug and dose :
Acute therapy —intravenous labetalol (Begin with 20 mg intravenously over 2
minutes followed at 10-minute intervals by doses of 20 to 80 mg up to a
maximum total cumulative dose of 300 mg or constant infusion of 1 to 2
mg/min )or hydralazine (Begin with 5 mg intravenously over 1 to 2
minutes , maximum bolus dose is 20 mg) as first-line agents for acute
therapy of severe hypertension.
but nimodipine, diazoxide, and ketanserin were probably best avoided.
oral nifedipine is an acceptable alternative to parenteral labetalol or
hydralazine for severe hypertension .
-Options for second-line therapy include labetalol or nicardipine by infusion
pump. Nitroprusside is administered as a last resort.
-Magnesium sulfate, which is usually administered to women with
preeclampsia, is never a substitute for prompt initiation of
antihypertensive treatment of severe hypertension as it has minimal
effects on blood pressure.
Long-term oral therapy —
preeclamptic women with severe hypertension remote
from term are stabilized and not delivered
immediately. Oral antihypertensive therapy is often
indicated for these patients. Options for oral
antihypertensive therapy are the same as for women
with preexisting hypertension .
Target blood pressure —
reducing mean arterial pressure by no more than 25
percent over 2 hours and achieving a target of 130 to
150 mmHg systolic and 80 to 100 mmHg diastolic.
2. Gestational hypertension —
The indications for and choice of antihypertensive
therapy in women with gestational hypertension are
the same as for women with preeclampsia.
3. Chronic (preexisting) hypertension —
Beneficial effects of treatment appear to be limited to
prevention of maternal morbidity and depend upon
the severity of the disease.
nonobese women under age 30 years with a confirmed
negative family history of hypertension may have
secondary hypertension, so causes of secondary
hypertension should be considered in those with
suggestive clinical features such as severe or
resistant hypertension, acute onset of hypertension,
metabolic abnormalities associated with either
renovascular hypertension (high plasma renin
activity) or primary aldosteronism (low plasma renin
activity, low serum potassium), or proven onset of
hypertension before puberty.
Baseline laboratory tests:
●Urinalysis •
●Urine culture •
●Creatinine •
●Glucose •
●Electrolytes •
●Quantitative analysis of urine protein
•
Indications for treatment —
we avoid treatment of pregnant women with mild hypertension
and no evidence of target organ damage, especially in the first
trimester, since blood pressure normally decreases as
pregnancy progresses into the second trimester.
In women already on antihypertensive therapy who have early
pregnancy blood pressures less than 120/80 mmHg, we would
consider tapering/discontinuing antihypertensive drugs and
closely monitoring the blood pressure response.
Our indications for initiating or reinstituting antihypertensive
therapy are persistent diastolic pressures of 95 to 99 mmHg,
systolic pressures ≥150 mmHg, or signs of hypertensive targetorgan damage.
Severe hypertension in pregnancy (blood pressure ≥160/110
mmHg) should be treated.
Complicated and secondary hypertension:
●Secondary hypertension. •
●Target-organ damage (eg, left ventricular hypertrophy,
microalbuminuria, retinopathy).
●Dyslipidemia. •
●Maternal age over 40 years old. •
●History of stroke. •
●Previous perinatal loss. •
●Diabetes •
•
(a blood pressure target of 110 to 129/65 to 79 mmHg in •
pregnant women with diabetes and chronic
hypertension)
Blood pressure goal —
in women without target-organ damage :systolic
pressure between 140 and 150 mmHg and diastolic
pressure between 90 and 100 mmHg
In women with target-organ damage: to keep the blood
pressure below 140/90 mmHg
THE END