Hypertensive Disorders of Pregnancy

Contributor: Sharon Keiser, MD

Date: January 2021

Definitions, classification and diagnostic criteria:

Chronic hypertension (CHTN)- SBP>140 or DBP>90 on 2 separate occasions at least 4 hours apart, diagnosed prior to pregnancy or before 20 weeks gestation or persisting longer than 12 weeks postpartum.

Gestational hypertension (GHTN)- SBP>140 or DBP>90 on two separate occasions at least 4 hours apart after 20 weeks gestation in women with previously normal blood pressure.

Severe GHTN/Preeclampsia with severe features– (SBP>160 or DBP>110) on two separate occasions at least 4 hours (unless antihypertensive therapy is initiated before this time).

Preeclampsia- GHTN plus new onset proteinuria, defined as either >300 mg protein on 24 hour urine or P:C ratio > 0.3 or 2+ protein on dipstick (only if other quantitative methods not available). The diagnosis of preeclampsia is not dependent on proteinuria. Without proteinuria, the diagnosis is considered with new-onset HTN and the onset of any of the following severe features:

1. Persistent cerebral or visual disturbances (HA, scotomata, hyperreflexia, seizure)
2. Pulmonary edema
3. Severe RUQ pain or epigastric pain (without other diagnosis)
4. Thrombocytopenia (platelets <100k/uL)
5. Elevated LFTs (2x upper limits of normal)
6. Serum creatinine >1.1mg/dL or doubling of creatinine without renal disease

Preeclampsia with severe features– Preeclampsia with SBP>160 or DBP>110 on two occasions at least 4 hours apart (unless hypertensive therapy is initiated before this time) or any severe features listed above are present.

CHTN with superimposed preeclampsia– Preeclampsia in a woman with a diagnosis of hypertension prior to pregnancy of diagnosed before 20 weeks.

Eclampsia– New-onset tonic-clonic, focal or multifocal seizures in the absence of other causative conditions such as epilepsy or drug use.

Risk factors for preeclampsia

1. Nulliparity
2. Preeclampsia in previous pregnancy
3. Gestational or pregestational diabetes
4. Thrombocytopenia
5. Prepregnancy BMI >30
6. AMA
7. Pregnancy resulting from ART
8. Multifetal gestations
9. SLE
10. Antiphospholipid syndrome
11. Renal disease
12. Obstructive sleep apnea

See guideline for low dose ASA use in these high risk conditions to decrease the risk for preeclampsia.

Preeclampsia without severe features & GHTN:

Antepartum Management <37 weeks

1. Outpatient management if complaint OR inpatient management if adherence to follow up visit is concern
2. Preeclampsia labs weekly- CBC, CMP,LDH
3. Twice weekly antenatal testing and serial growth scans
4. Consider BMS unless contraindicated
5. The addition of antihypertensive medication are not recommended. No improvement in perinatal outcome is noted and severe disease may be masked.
6. Delivery at 37 weeks if not indicated sooner

Antepartum > 37 weeks gestation– DELIVER

Intrapartum Management

1. Continuous FHR monitoring
2. HELLP labs every 12 hours
3. Use of MgSO4 for seizure prophylaxis is recommended if severe features develop; consideration for use in GHTN and preeclampsia without severe features can be individualized
4. Monitor for development of severe features
5. Mode of delivery determined by routine obstetric indications

Postpartum Management

1. Closely monitor BP, UOP and symptoms.
2. Antihypertensive medications to keep SBP <150; DBP <100
3. All patients with these diagnoses should be given discharge instructions for s/s of worsening hypertensive disease and seen in 3-7 days postpartum in outpatient setting for BP check.
4. Contraception- estrogen containing contraception should not be given to any patient with a hypertensive disorder of pregnancy until hypertension is controlled/resolved. Consider LARC, depo-provera or progesterone only pills.
5. Counsel about low-dose ASA as prevention in subsequent pregnancies.

Preeclampsia with Severe Features

Antepartum Management <23 weeks gestation (or EFW <400 grams or umbilical cord Doppler with persistent REDF)- DELIVER

Antepartum Management 23-34 weeks gestation

1. Inpatient hospitalization until delivery
2. BMZ if appropriate; do not delay delivery for BMZ maturity if maternal or fetal status is deteriorating
3. Initiate MgSO4 during initial assessment period if severe features are present; may discontinue at steroid maturity if managing conservatively
4. Serial preeclampsia labs and blood pressure monitoring
5. Daily NST with weekly BPP; growth ultrasound every 3 weeks until delivery
6. Daily weights
7. Consider conservative management if:

• Maternal and fetal status are reassuring AND patient agrees/understands risk
• Diagnosis is made by BP criteria only AND antihypertensive medication keeps SBP<160 and DBP<110. Medications include nifedipine XL p.o. (max 120 mg/day), labetalol p.o. every 6 to 8 hours (max 2400 mg/day), hydralazine p.o. (max 300 mg/day).

8. Conservative management contraindicated with any of the following:

• Maternal desire for delivery
• Oliguria (UOP less than 30 cc/hour x4 hours) or renal failure (Cr > 1.1 mg/dL or twice baseline)
• Neurologic symptoms
• Nonreassuring fetal assessment or fetal death
• Vaginal bleeding or other signs of abruption
• Uncontrolled severe range BPs
• Development of HELLP syndrome
• Pulmonary edema or myocardial infarction
• IUGR (relative contraindication)

Antepartum Management >34 weeks gestation- Deliver giving BMZ during induction (do not delay delivery for BMZ)

Intrapartum Management

1. Continuous fetal monitoring
2. Preeclampsia labs every 12 hours or more frequent if indicated (CBC, CMP, LDH, +/- uric acid)
3. Initiate magnesium sulfate (see table) with induction of labor or cesarean
4. Strict I/Os
5. Monitor respirations, DTRs, maternal mental status every 2 hours
6. IOL may be considered for pregnancies greater than 30 weeks or earlier, if favorable cervix; cesarean delivery may be considered with nonreassuring fetal status or unfavorable cervix prior to 30 weeks
7. Antihypertensives should be utilized to keep SBP<160 and DBP<110. Oral medications as mentioned previously nifedipine, labetalol, hydralazine.  See table for IV administration of antihypertensive medications.
8. Regional anesthesia is preferred. General anesthesia carries higher risk of aspiration, failed induction, or stroke.  Neuraxial anesthesia is contraindicated in the presence of a coagulopathy.  No consensus on lower limit for platelet count and neuro axial anesthesia (risk of hematoma is low in patients with platelet count greater than 70K).  Continue MgSO4 during cesarean.

Postpartum Management

1. Continue MgSO4 for 24 hours (or 24 hours from last seizure activity if applicable)
2. Strict I/Os and daily weights for entire postpartum hospital course
3. Maintain BPs < 150 systolic and <100 diastolic. Utilize–nifedipine XL p.o. (max 120 mg/day), labetalol p.o. every 8-12 hours (max 2400 mg/day), HCTZ 12.5 to 50 mg/day (may reduce milk volume)
4. All patients must be evaluated within 1 week after hospital discharge for a blood pressure check
5. Contraception–estrogen-containing contraception should not be given to any patient with a hypertensive disorder of pregnancy until hypertension has resolved; consider progesterone only pills, Depo-Provera, or LARC
6. Counsel regarding low-dose aspirin as a preventative and subsequent pregnancies

Eclampsia

Supportive Care

1. Call for help in alert anesthesia
2. Prevent maternal injury and aspiration
3. Place in lateral decubitus position
4. Monitor vital signs
5. Administer oxygen

Management

1. Initiate magnesium sulfate for seizure prophylaxis after seizure activity has stopped (See table)
2. Reduce blood pressure (range for SBP 140 to <160 and DBP 90 to <110)
3. Initiate a course of betamethasone if appropriate
4. Fetal monitoring (after seizure activity has stopped). During/immediately after eclamptic seizures, FHRT may show prolonged decelerations and/or bradycardia which usually resolve after 10 minutes or correction of maternal hypoxemia
5. Move towards delivery (eclampsia is not an indication for cesarean section)
6. Continue MgSO4 for 24 hours after the resolution of seizure activity
7. Additional seizure activity (occurs in approximately 10% of patients). Give an additional 2 to 4 g of MgSO4 IV over 5 min.  In cases refractory to magnesium (still having seizures 20 minutes after bolus or greater than 2 recurrences), give sodium amobarbital (250 mg IV), thiopental or phenytoin.  Consider head CT/MRI.

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References

1. Gabbe, Stephen, Obstetrics: Normal and problem pregnancies.  Ch 33 – Hypertension
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