What is the management of second trimester preeclampsia?

Management of Second Trimester Preeclampsia

Women with second trimester preeclampsia require immediate hospitalization for comprehensive maternal and fetal assessment, with the management strategy determined by gestational age: those at ≥24 weeks should receive expectant management with aggressive monitoring at a perinatal center, while those <24 weeks should be counseled about pregnancy termination given the high maternal morbidity and poor perinatal outcomes. 1, 2

Initial Assessment and Hospitalization

• All women with newly diagnosed preeclampsia must be hospitalized initially to confirm diagnosis, assess disease severity, and establish baseline maternal and fetal status 1, 3
• Maternal monitoring should include blood pressure measurements every 4 hours (more frequently if severe hypertension develops) 3, 4
• Obtain baseline laboratory tests including hemoglobin, platelet count, liver transaminases, creatinine, and uric acid—these must be repeated at least twice weekly throughout expectant management 1, 3
• Perform clinical assessment for clonus and neurological symptoms at each evaluation 1
• Initial fetal assessment should confirm well-being with ultrasound evaluation of fetal biometry, amniotic fluid volume, and umbilical artery Doppler 1, 3

Gestational Age-Based Management Strategy

Before 24 Weeks Gestation

• Pregnancy termination should be strongly recommended due to high maternal morbidity (40% complication rate) and extremely poor perinatal survival (6.7%) 2
• Women who decline termination and continue pregnancy face significant risks including progression to severe disease, HELLP syndrome, and eclampsia with minimal chance of neonatal survival 2
• If expectant management is attempted despite recommendations, transfer to a tertiary perinatal center with maternal-fetal medicine expertise is mandatory 1, 5

Between 24-32 Weeks Gestation

• Expectant management with aggressive monitoring at a perinatal center is the preferred approach, as it significantly improves perinatal survival (76.4% vs 35%) and reduces neonatal complications compared to immediate delivery 2, 6
• Average pregnancy prolongation of 13-15 days can be achieved safely with appropriate monitoring 2, 6
• This approach results in higher birth weights (880g vs 709g) and reduced neonatal intensive care unit stays (20 vs 37 days) 2, 6

Between 32-34 Weeks Gestation

• Continue expectant management with intensive monitoring if maternal and fetal conditions remain stable 1, 7
• Administer corticosteroids for fetal lung maturity according to standard protocols 1, 8
• Serial fetal surveillance with ultrasound should be performed every 2 weeks if initial assessment is normal, more frequently if fetal growth restriction is present 1, 3

Blood Pressure Management

Severe Hypertension (≥160/110 mmHg)

• Treat urgently in a monitored setting with oral nifedipine 10mg, repeat every 20 minutes to maximum 30mg 3, 4
• Alternative: IV labetalol 20mg bolus, then 40mg after 10 minutes if needed, followed by 80mg every 10 minutes to maximum 220mg 3, 4
• Alternative: IV hydralazine can also be used 1, 4

Non-Severe Hypertension (140-159/90-109 mmHg)

• Initiate oral antihypertensive therapy targeting diastolic BP of 85 mmHg and systolic BP 110-140 mmHg 1, 3, 4
• First-line agents include oral labetalol, nifedipine, or methyldopa 1, 5
• Never use ACE inhibitors as they are contraindicated in pregnancy 5

Magnesium Sulfate for Seizure Prophylaxis

• Administer magnesium sulfate to all women with severe hypertension (≥160/110 mmHg) or any neurological signs/symptoms 1, 3
• Loading dose: 4g IV over 20 minutes or 10g IM 1, 9
• Maintenance: 1g/hour IV infusion or 5g IM every 4 hours 1, 9
• Continue for 24 hours postpartum 1, 9
• Therapeutic serum levels range from 2.5-7.5 mEq/L; monitor for toxicity (loss of deep tendon reflexes occurs at 10 mEq/L, respiratory paralysis may occur at this level) 9

Fluid Management

• Strictly limit total fluid intake to 60-80 mL/hour to prevent pulmonary edema 1, 3, 4
• Aim for euvolemia—do not "run dry" as this increases acute kidney injury risk 1, 5
• Plasma volume expansion is not recommended 1, 4

Fetal Monitoring Protocol

• Perform ultrasound assessment of fetal biometry, amniotic fluid, and umbilical artery Doppler at diagnosis 1, 3
• Repeat ultrasound every 2 weeks if initial assessment is normal 1, 4
• If fetal growth restriction is present, increase frequency of amniotic fluid and Doppler assessments 1, 5
• Daily fetal movement counting and non-stress testing as clinically indicated 7

Mandatory Delivery Indications (Any Gestational Age)

Deliver immediately if any of the following develop, regardless of gestational age:

• Repeated episodes of severe hypertension despite treatment with 3 classes of antihypertensive agents 1, 3
• Progressive thrombocytopenia 1, 4
• Progressively abnormal liver or renal function tests 1, 4
• Pulmonary edema 1, 4
• Severe intractable headache, repeated visual scotomata, or eclamptic seizures 1, 4
• Non-reassuring fetal status including reversed end-diastolic flow on umbilical artery Doppler 1, 5
• Placental abruption 1, 6
• Maternal oxygen saturation <90% 1

Critical Pitfalls to Avoid

• Do not attempt to classify preeclampsia as "mild" versus "severe"—all cases can deteriorate rapidly and become emergencies 1, 4
• Neither serum uric acid level nor degree of proteinuria should be used as isolated indications for delivery 1
• Avoid NSAIDs for postpartum analgesia, especially with renal dysfunction—use alternative pain relief 1
• Do not use low molecular weight heparin for preeclampsia prevention 1
• Be aware that calcium channel blockers combined with IV magnesium may cause myocardial depression requiring close cardiac monitoring 5

Postpartum Management

• Continue close monitoring for at least 3 days postpartum as eclampsia can develop de novo in the postpartum period 1, 4
• Monitor blood pressure at least every 4-6 hours while awake 1, 4
• Continue magnesium sulfate for 24 hours after delivery 1, 9
• Maintain antihypertensive therapy and taper slowly only after days 3-6 postpartum unless BP falls below 110/70 mmHg 1, 4
• Review within 1 week if still requiring antihypertensives at discharge 1, 4
• All women should be reviewed at 3 months postpartum when BP, urinalysis, and laboratory tests should have normalized 1, 4

Long-Term Counseling

• Counsel all women about increased lifetime cardiovascular risk including stroke, diabetes mellitus, venous thromboembolism, and chronic kidney disease 1, 3, 4
• Women with history of second trimester preeclampsia should receive low-dose aspirin (75-162 mg daily) before 16 weeks gestation in future pregnancies 1, 3
• Consider supplemental calcium (1.2-2.5 g daily) if dietary intake is low (<600 mg/day) 1