Approach to hypertensive disorders in pregnancy: Clinical sciences

Hypertension in pregnancy is a spectrum of disorders, all characterized by elevated blood pressure. These include chronic hypertension, gestational hypertension, preeclampsia without or with severe features, HELLP, and eclampsia.

Your first step in evaluating a patient who presents with a hypertensive disorder of pregnancy is to perform a CABCDE assessment along with a primary obstetric survey to determine if they’re stable or unstable.

If the patient is unstable, check for uncontrolled bleeding and control any hemorrhage, as severely elevated blood pressure may cause a placental abruption. Next, stabilize their airway, breathing, and circulation and consider intubation when appropriate.

Obtain IV access and continuously monitor maternal vital signs. As for the primary obstetric survey, monitor the fetal heart rate and contraction pattern; possibly test for rupture of amniotic membranes; and consider checking cervical dilation if indicated.

Here’s a clinical pearl! Urgent hypertension is defined as 160/110 or higher that persists after retake in 15 to 20 minutes; this requires antihypertensive medication to reduce the risk of maternal stroke.

Let’s take a look at stable patients. Alright, now that unstable patients are taken care of, let’s talk about stable patients. First, obtain a focused history and physical examination. This should include an accurate blood pressure measurement. A systolic blood pressure greater than or equal to 140, a diastolic blood pressure greater than or equal to 90, or both is considered abnormal during pregnancy. Once you have recognized the patient has elevated blood pressure, it’s time to investigate further; the first step is to assess the patient’s gestational age.

Let’s take a look when the patient is less than 20 weeks gestation.

If the patient is less than 20 weeks gestation, assess whether they have a history of hypertension prior to pregnancy. If the patient does report a history of hypertension, your diagnosis is chronic hypertension.

If the patient denies any history of hypertension, still consider a diagnosis of chronic hypertension and continue to monitor them closely throughout the remainder of the pregnancy.

If a second elevated blood pressure is recorded prior to 20 weeks of gestation, the patient meets the diagnostic criteria for chronic hypertension.

However, if they remain normotensive, the elevated blood pressure simply represents an isolated elevated blood pressure in pregnancy and not a true hypertensive disorder.

Okay, let’s shift our focus to patients who present with hypertension from 20 weeks of gestation through 12 weeks postpartum with abnormal blood pressure.

When a pregnant patient who is greater than or equal to 20 weeks gestation has abnormal blood pressure, monitor them closely to see if any repeat elevated blood pressure is noted.

If no repeat blood pressures are elevated, continue to monitor them at subsequent prenatal visits, though they do not meet the criteria for a true hypertensive disorder of pregnancy.

If a second elevated blood pressure is recorded, specifically a systolic pressure of at least 140, or a diastolic pressure of at least 90, or both, and it has been at least 4 hours since the first elevated measurement, you have diagnosed a hypertensive disorder of pregnancy.

Your next step is to order labs to help determine the specific disorder present. This will include a CBC, CMP, LDH, a urine protein to creatinine ratio, also known as P/C ratio, and possibly a 24-hour urine collection to measure total protein. A uric acid measurement can also be helpful in some cases.

Once these labs are sent, assess if the patient has any history of hypertension prior to pregnancy.

Let’s take a look when the patient reports no history of chronic hypertension either during or outside of pregnancy.

If your patient reports no history of chronic hypertension, consider either gestational hypertension or preeclampsia. To make your diagnosis, review lab results, specifically the urine P/C ratio to assess for proteinuria. Proteinuria is defined as a urine P/C ratio greater than or equal to 0.30, or a 24-hour urine protein with at least 300 mg of protein.

At the same time, assess for signs or symptoms of preeclampsia, which include new-onset headache, visual changes, right upper quadrant or epigastric pain, and possibly shortness of breath.

If all labs are normal, the urine P/C ratio is less than 0.30, and the patient is asymptomatic, your diagnosis is gestational hypertension.