Preeclampsia

Preeclampsia is new hypertension (blood pressure 140/90 mmHg or more on two readings 4 hours apart) after 20 weeks of pregnancy, with proteinuria or features of maternal organ or placental dysfunction. It arises from poor placental implantation with widespread endothelial injury. It is an important cause of maternal and perinatal death in Kenya.

• Risk factors: first pregnancy, previous preeclampsia, chronic hypertension, diabetes, kidney disease, twin pregnancy, obesity, age above 35 years, HIV, lupus, antiphospholipid syndrome.
• Aspirin from 12 weeks and calcium supplementation in low intake areas lower the risk.
• Delivery of the placenta is the only cure.

Most women have no symptoms and the diagnosis is made at antenatal visits. Others have headache, visual disturbance, epigastric or right upper quadrant pain, nausea, vomiting and sudden facial or hand oedema, with brisk reflexes or clonus.

• Blood pressure 140/90 mmHg or more with urine protein 1 plus or more.
• Fundal height small for dates suggests growth restriction.
• Differential diagnosis: chronic hypertension, gestational hypertension, chronic kidney disease, lupus nephritis, acute fatty liver of pregnancy, thrombotic thrombocytopenic purpura, urinary tract infection, normal pregnancy oedema.
• Complications: eclampsia, HELLP syndrome, placental abruption, stroke, pulmonary oedema, acute kidney injury, fetal growth restriction, preterm birth, stillbirth, maternal death.

The diagnosis rests on blood pressure and either proteinuria or organ dysfunction after 20 weeks.

• Blood pressure with a correct cuff size, seated, after 5 minutes of rest, two readings 4 hours apart (or one reading of 160/110 mmHg or more confirmed within 15 minutes).
• Proteinuria: dipstick 1 plus or more, urine protein to creatinine ratio 30 mg/mmol or more, or 24 hour protein 300 mg or more.
• Organ dysfunction: platelets below 100 x 10^9/L, creatinine above 90 micromol/L, alanine or aspartate aminotransferase twice the upper limit, pulmonary oedema, new headache or visual symptoms.
• Full blood count, creatinine, liver enzymes, lactate dehydrogenase, uric acid, urine protein to creatinine ratio, coagulation screen if platelets are low; ultrasound for growth, liquor volume and umbilical artery Doppler; cardiotocography.

The principle is to control blood pressure, prevent seizures with magnesium sulphate when severe, and deliver at the right time.

• Supportive: admit for confirmation; rest; normal diet without salt restriction; measure blood pressure 4-hourly and fetal movements daily; fluid restriction to 80 mL per hour total when severe; urinary catheter with hourly output.
• Pharmacological: aspirin 150 mg oral at night from 12 weeks to 36 weeks for prevention; calcium 1.5 g elemental oral daily where intake is low; for blood pressure of 140/90 mmHg or more give labetalol 200 mg oral every 8 to 12 hours (maximum 2.4 g daily) or nifedipine modified release 30 to 60 mg oral once daily (maximum 120 mg) or methyldopa 250 to 500 mg oral 8-hourly (maximum 3 g daily), aiming for 110 to 135/85 mmHg; for 160/110 mmHg or more give labetalol 20 mg IV over 2 minutes then 40 mg, 80 mg and 80 mg at 10 minute intervals (maximum 220 mg), or nifedipine immediate release 10 mg oral repeated once after 30 minutes, or hydralazine 5 mg IV then 5 to 10 mg every 20 to 30 minutes (maximum 20 mg); magnesium sulphate 4 g IV over 20 minutes then 1 g per hour for 24 hours for severe features; betamethasone 12 mg IM twice, 24 hours apart, between 24 and 34 weeks; give oxytocin 10 IU IM after birth and avoid ergometrine.
• Procedures: induction of labour with misoprostol 25 micrograms vaginal 6-hourly (maximum 4 doses) or a Foley catheter with a 30 mL balloon, then oxytocin starting at 2 mU/minute and doubling every 30 minutes to a maximum of 32 mU/minute; caesarean section for obstetric reasons or fetal compromise; delivery at 37 weeks if no severe features and after stabilisation if severe features appear.
• Special groups: asthma uses nifedipine instead of labetalol; kidney disease reduces magnesium sulphate to 0.5 g per hour with monitoring of reflexes and urine output.
• Red flags: blood pressure 160/110 mmHg or more, severe headache, visual disturbance, epigastric pain, seizure, platelets below 100 x 10^9/L, oliguria below 30 mL per hour, reduced fetal movements.
• Follow-up: antenatal review twice weekly until delivery; check blood pressure at 6 hours, daily for 5 days and at 2 weeks and 6 weeks after birth; urine protein at 6 weeks; annual blood pressure, glucose and lipids for life.