Does this pregnant patient have hypertension?

How do you diagnose and treat hypertension in a pregnant patient?

Hypertension complicates 5-15% of pregnancies. Hypertensive disorders of pregnancy are classified as the following:

  • Preexisting hypertension: Systolic pressure >= 140 mmHg and / or diastolic pressure >= 90 prior to pregnancy, present before the 20th week of pregnancy, or present more than 12 weeks post-partum. This complicates approximately 3% of pregnancies.

  • Gestational hypertension: Systolic blood pressure >= 140 mmHg and / or diastolic pressure >= 90 after 20 weeks gestational age in women previously normotensive. Blood pressure should be elevated on at least two occasions at least 6 hours apart. Present in 6-15% of pregnancies.

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  • Preeclampsia: Systolic pressure >= 140 mmHg and / or diastolic pressure >= 90 and new onset proteinuria or evidence of other end-organ dysfunction including thrombocytopenia, impaired liver function, reduced eGFR, pulmonary edema or cerebral symptoms after 20 weeks gestational age. Preeclampsia occurs in 5-8% of pregnancies in the United States, classified as severe in 25% of cases. About 25% of patients initially diagnosed with gestational hypertension progress to preeclampsia. Risk factors for its development include prior preeclampsia, first pregnancy, family history, multiple gestations, obesity, renal disease, diabetes and advanced maternal age.

What tests to perform?

Symptoms and signs

Severity of hypertension should be assessed.

Hypertension is considered “severe” when the systolic blood pressure is > 160 mmHg and/or diastolic blood pressure is > 110 mmHg. Patients should be monitored for symptoms of preeclampsia such as severe headaches, visual changes, epigastric pain, nausea, vomiting.

Fetal symptoms and signs

Fetal wellbeing should be assessed with serial biophysical profiles or nonstress tests with amniotic fluid estimation. Ultrasonographic estimation of fetal weight is used to assess for intrauterine growth restriction.

Lab testing

Assess for proteinuria: > 0.3 grams of protein/24 hours suggests preeclampsia in women without proteinuria at baseline. Elevated serum creatinine, uric acid, hepatic transaminases, and thrombocytopenia are also suggestive of preeclampsia.

How should pregnant patients with hypertension be managed?

Medication management for women with severe hypertension (>160/110) is recommended. A recent randomized controlled trial demonstrated that even tighter blood pressure control (goal diastolic blood pressure < 85 mmHg) was safe for mother and fetus and prevented development of severe hypertension but not preeclampsia.

The American College of Obstetrics and Gynecology recommends treatment for all women with a systolic blood pressure >160 and diastolic pressures of > 110. Target levels are < 160/110, at minimum, although many providers aim for 140-150/90-100. In patients with known end-organ damage, goals should be < 140/90.

Choice of antihypertensive agents:

Initial therapy recommendations include

  • Labetolol orally started at 100 mg, two to three times daily, with a maximum total dose of 1200 mg/day

  • Methyldopa orally started at 250 mg twice with maximum of 3 gm/day. Major side effect is sedation

  • Nifedipine (long-acting) orally started at 30 mg a day, titrated up to 60 mg twice daily

Agents to be avoided include angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, and renin inhibitors due to birth defects primarily seen after the first trimester. Patients should be taken off these agents if they are attempting to become pregnant.

Early delivery can be considered for patients with severe hypertension and/or preeclampsia. Magnesium sulfate is used in severe preeclampsia for seizure prophylaxis.

In a multicenter trial of 700 patients there was benefit to labor induction at 37 weeks versus expectant management for women with preeclampsia. There were fewer adverse maternal outcomes and a lower rate of cesarean sections.

Antenatal steroids (betamethasone) should be given to women diagnosed with preeclampsia between 24 and 34 weeks gestation to promote fetal lung maturity.

What happens to pregnant patients with hypertension?

Most women with gestational hypertension become normotensive within the first week postpartum. By definition, all should be normotensive by 12 weeks post-partum, otherwise they are considered to have chronic hypertension. This occurs in approximately 15% of patients with gestational hypertension.

How to utilize team care?

Patients with any form of hypertension in pregnancy should be considered for a high-risk obstetrics consultation. Therapy can also be co-managed with a hypertension specialist, such as a nephrologist with expertise in pregnancy.

Pharmacists can assist with ensuring drug safety in pregnant women and can assist with possible drug interactions in pregnant patients who may be taking more than one medication.

Dietitians can assist with healthy diets with appropriate quantities of sodium for patients with hypertension.

Are there clinical practice guidelines to inform decision making?

The American College of Obstetricians and Gynecologists (ACOG) recommends:

For women with chronic hypertension who are at greatly increased risk of adverse pregnancy outcomes (a history of early-onset preeclampsia and preterm delivery at less than 34 weeks of gestation of preeclampsia in more than one prior pregnancy) initiating the administration of daily low dose aspirin (60-80 mg) beginning in the first trimester is suggested.