Hypertension in pregnancy

Most common medical disorder during pregnancy.

Hypertensive disorders of pregnancy include gestational hypertension and preeclampsia.

Almost 10% of pregnant women have hypertension.

In the United States chronic hypertension develops in 2% or more of pregnancies.

Most pregnancies among individuals with well-controlled chronic hypertension are uncomplicated, but individuals with chronic hypertension are at increased risk for maternal morbidity, preeclampsia, kidney failure, pulmonary edema, myocardial infarction, placental abruption, gestational diabetes, stroke, death, and poor fetal/neonatal outcomes of growth restriction, preterm birth, congenital abnormalities, still birth, and prenatal death.

Chronic hypertension in pregnancy disproportionately affects Black women and is associated with 3 to 5 times the risk of preeclampsia, placental abruption, preterm birth, or small for gestational age birthweight, or perinatal death.

Chronic hypertension in pregnancy is associated with 5 to 10 times the risk of maternal death, heart failure, stroke, pulmonary edema, or acute kidney injury.

The prevalence of chronic hypertension among pregnant women has increased significantly over the last number of decades.

The frequency of hypertension first detected during pregnancy has also increased.

Hypertensive disorders of pregnancy, have increased in the US coming contribute to adverse maternal and Child health outcomes and can increase the woman’s lifetime risk of cardiovascular disease.

Hypertension is one of the major causes of maternal and fetal mortality, and these conditions are associated with major changes in the risk for a future disease for the mother.

Pregnant women with a history of hypertensive disease of pregnancy are at great risk of cardiovascular disease-related mortality.

Women with a history of hypertensive disorders of pregnancy have increased risk for cardiovascular disease and related mortality, including 2-2.5 times the risk for ischemic heart disease, congestive heart failure, and stroke and 3-4 times the risk for hypertension.

Hypertensive disorders of pregnancy are classified into: chronic hypertension diagnosed before pregnancy or before 20 weeks’ gestation, gestational hypertension diagnosied at equal to or greater than 20 weeks of pregnancy, or preeclampsia.

Hypertensive disease of pregnancy is a spectrum: includes gestational hypertension, chronic hypertension, preeclampsia, and eclampsia.

Hypertensive disease of pregnancy affects up to 8.2% of deliveries in the United States.

It is presumed the older maternal age at delivery and higher rates of obesity account partially for these increases.

Hypertension preexists in 1% of pregnant women, and gestational hypertension without proteinuria develops in 5 to 6% of patients, and preeclampsia develops in 2 percent.

Up to 25% of women with chronic hypertension may develop superimposed preeclampsia and up to 35% with gestational hypertension may progress to preeclampsia.

Associated with increased maternal and perinatal morbidity and mortality.

Pre-existing hypertension and gestational hypertension before 34 weeks of pregnancy are associated with an increased risk of maternal and perinatal complications.

Maternal complications include abruptio placentae, stroke preeclampsia.

Fetal complications include prematurity, stillbirth, low birth weight and neonatal death.

Chronic hypertension in pregnancy is defined as a systolic blood pressure of 140 mm Hg or 90 mm Hg before pregnancy, or for women who first present for care during pregnancy, before 20 weeks of gestation.

Chronic hypertension prevalence is increasing because of increased rates of obesity and a delay in childbearing to ages when chronic hypertension is more common.

Chronic hypertension is observed in 1-5% of pregnant women.

Preeclampsia is in the differential diagnoses of any hypertension from 20 weeks gestation .

The incidence among African-Americans is about 2.5%.

Treatment during pregnancy may be associated with a reduction in fetal growth.

The risks of intrauterine growth restriction in and low birth weight increase with aggressive treatment of maternal hypertension, probably caused by reduced uretoplacental perfusion caused by excessive blood pressure reduction.

In pregnant women with mild chronic hypertension, targeting a blood pressure of less than 140/90 mmHg is associated with better pregnancy outcomes than a strategy of reserving treatment only for severe hypertension, with no increase the risk of small for gestational age birthweight.

Odds of intrauterine growth restriction with hypertension in pregnancy are 2 to 3 times the odds in pregnant women without hypertension.

In a randomized trial comparing less-tight versus tight control of mild to moderate non-proteinuric hypertension in pregnancy: there was no significant difference between groups not differing in the frequency of serious maternal complications, including the development of preeclampsia (Mangee LA et al).

The risk of complications doubles for women over the age of 40 compared to younger women.

Most women with chronic hypertension have good pregnancy outcomes, albeit they have increased risk for complications compared to the general population.

Adverse outcomes increased with the severity of hypertension and end-organ damage.

Chronic hypertension in pregnancy associated with an increased frequency of preeclampsia, 17-25%, compared to 3-5% in the general population.

Chronic hypertension associated with an increased abruptio placenta, fetal growth restriction, pre-term birth, and cesarean section.

Preeclampsia rates increase with increasing duration of hypertension in pregnancy, and is the leading cause of preterm birth and cesarean delivery in this group of patients.

In a study of 861 women with chronic hypertension, 22% developed preeclampsia, and nearly half of these women presented at less than 34 weeks of gestation, a time earlier than is typical in women without antecedent hypertension (Mccowan LM et al).

Women with chronic hypertension with superimposed preeclampsia are at increased risk for having a small for gestational age infant, and for placental abruptio compared to women with hypertensionand no ecclampsia.

Fetal growth restriction occurs in 10-20% of pregnancies associated with chronic hyperetension.

Associated with 5 times risk of preterm birth, and 50% increase in the risk of giving birth to a small for gestation age infant.

Associated with a two times risk of placental abruption compared to normotensive women (1.56% vs 0.58%).

Chronic hypertension in pregnancy associated with increased risk of stillbirth.


Treatment of hypertension in pregnancy is warranted if blood pressure if high enough to pose a risk of stroke: 160 mm Hg systolic or greater than 105 mmHg diastolic, or if there is associated renal or cardiovascular disease.

Randomized trials of mild chronic hypertension in pregnancy have failed to show improvements a major complications.

Treatment of mild chronic hypertension has not decreased the incidence of superimposed preeclampsia or other major maternal complications.

A randomized study found no significant differences in the rates of major adverse perinatal outcomes or overall serious maternal complications with less tight versus tight control of blood pressure: less tight control was associated with a higher rates of severe maternal hypertension (Magee LA et al).

Two antihypertensive medications labetalol and nifedipine are preferred in pregnancy due to their safety profiles.

Angiotensin converting enzyme inhibitors in angiotensin receptor blocker‘s should not be used during pregnancy as they are associated with fetal malformations and neonatal complications such as kidney failure and growth restriction.

Low-dose aspirin is recommended for all pregnant patients with chronic hypertension after 12 weeks gestation for preeclampsia prevention.

Antihypertensive therapy in pregnancy is recommended for persistent systolic blood pressure values greater than or equal to 140 mmHg with diastolic blood pressure values of greater than 90 mmHg.

The USPSTF recommends screening for hypertensive disorders in pregnant persons with blood pressure measurements throughout pregnancy.

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