Preeclampsia (pregnancy toxemia)
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Classification of hypertensive disorders in pregnancy
| Type | Definition | Features |
|---|---|---|
| Gestational hypertension | PAS ≥ 140 mmHg or PAD ≥ 90 mmHg after 20 SA + without proteinuria or organ dysfunction | Isolated hypertension without other preeclampsia criteria + may precede preeclampsia → monitor closely |
| Preeclampsia without signs of severity | HTA (PAS ≥ 140 or PAD ≥ 90) after 20 SA + proteinuria ≥ 300 mg/24 h (or pro/creat ratio ≥ 30 mg/mmol) | hypertension + proteinuria + no severe organ damage + close monitoring |
| Severe preeclampsia | Preeclampsia + ≥ 1 severity criterion (see below) | Indication for delivery according to gestational age + magnesium sulfate mandatory |
| Eclampsia | Tonic-clonic convulsions occurring in the context of preeclampsia and not explained by another cause | Neurological and obstetrical emergency + immediate IV magnesium sulfate + urgent delivery |
| HELLP syndrome | Hemolysis + elevated LDH + elevated AST + platelets < 100,000/µL | Severe complication → see dedicated data sheet |
| Chronic hypertension with added preeclampsia | Pre-existing hypertension + onset or worsening of proteinuria after 20 weeks' gestation | Worse prognosis than normotensive preeclampsia |
Pre-eclampsia severity criteria
- Severe hypertension : PAS ≥ 160 mmHg + or PAD ≥ 110 mmHg on two occasions ≥ 4 hours apart
- Kidney damage : creatinine ≥ 97 µmol/L (or doubling of baseline creatinine) + or oliguria (< 500 mL/24 h)
- Liver damage : ASAT or ALAT > 2× LSN + or severe and persistent epigastric or right hypochondrium pain unresponsive to analgesics
- Neurological damage : persistent severe headaches resistant to analgesics + visual disturbances (scotomas + diplopia + cortical blindness) + sharp osteotendinous reflexes + neuromuscular hyperexcitability (prodromal eclampsia)
- Lung involvement : pulmonary edema
- Hematological disorders : thrombocytopenia < 100 000/µL + DIC
- Fetal damage : severe intrauterine growth retardation + severe oligohydramnios + pathological umbilical Doppler (absent or inverted diastole)
Risk factors and aspirin prevention
- High-risk factors (≥ 1 factor → aspirin recommended) : antecedent preeclampsia (risk × 8) + multiple pregnancy + chronic hypertension + diabetes (type 1 or 2) + chronic kidney disease + antiphospholipid syndrome + lupus + primiparous with ≥ 2 moderate factors
- Moderate risk factors: primiparous + obese (BMI > 30) + family history of 1st-degree preeclampsia + age ≥ 35 years + inter-pregnancy interval > 10 years + IVF pregnancy
- Low-dose aspirin (81 mg/d): initiated between 12 and 16 SA (ideally before 16 SA) + taken in the evening at bedtime + continued until 36 SA + reduced risk of preeclampsia by 17-24 % in the general population + and up to 62 % in high-risk pregnancies + mechanism: inhibition of platelet TxA2 → reduced vasospasm + improved uteroplacental perfusion
- Calcium : calcium supplementation 1.5-2 g/day for women with inadequate dietary calcium intake → reduces risk of preeclampsia + especially in low-income countries
- Combined 1st trimester screening (11-14 SA) : serum markers (PlGF - placental growth factor + PAPP-A) + uterine artery Doppler + BP + BMI → calculation of risk of early preeclampsia (< 34 SA) → sensitivity 90 % with 10 % false positives → guides aspirin prescription
Support
- Preeclampsia without signs of severity (34-37 SA) : hospitalization + close maternal and fetal monitoring + antihypertensives if BP persists ≥ 140/90 → labetalol per os (100-400 mg × 2-3/d) + or nifedipine LP + target BP < 140/90 + DO NOT aim for too low a BP (risk of placental hypoperfusion) + delivery at 37 SA recommended (HYPITAT trial)
- Severe preeclampsia (< 34 SA) : hospitalization in a level 3 center + magnesium sulfate IV (4-6 g loading + 1-2 g/h maintenance) + antihypertensives IV (labetalol IV + or hydralazine + or rapid oral nifedipine) + corticoids (betamethasone 12 mg IM × 2 if < 34 SA for lung maturation) + continuous fetal monitoring + delivery decision based on maternal and fetal benefit/risk balance according to gestational age
- Severe preeclampsia (≥ 34 SA) : delivery after BP stabilization + administration of magnesium + corticosteroids if < 37 SA
- Antihypertensives contraindicated in pregnancy : ACE inhibitors + ARB II (teratogenic in the 2nd and 3rd trimesters - renal malformations + fetal anuria) → use labetalol + nifedipine + methyldopa + hydralazine
- Magnesium sulfate - prevention and treatment of eclampsia : 4-6 g IV in 15-20 min (loading) + 1-2 g/h (maintenance) + monitoring: FR (> 12/min) + ROT (present) + diuresis (> 25 mL/h) + magnesemia (target 2-3.5 mmol/L) + antidote: calcium gluconate 1 g IV
- Post-partum monitoring and treatment : BP may worsen in the 48-72 h postpartum + maintain antihypertensive drugs + monitor BP + platelets + creatinine + transaminases for at least 48-72 h + breastfeeding compatible with labetalol + nifedipine + methyldopa
Call 911 or go immediately to the obstetric emergency room if a pregnant woman (or one who has given birth within 7 days) presents with severe headaches + visual disturbances (spots + flashes + visual blur) + epigastric pain + sudden swelling of the face or hands + or convulsions - these signs suggest severe preeclampsia or eclampsia requiring emergency management. For the prescription of preventive aspirin in early pregnancy and prenatal blood pressure monitoring, Clinique Omicron offers consultations at its points of service in Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
Consult at Clinique Omicron
Clinique Omicron's specialized physicians and nurse practitioners (NPs) assess preeclampsia risk factors at the first prenatal check-up, prescribe aspirin 81 mg/d before 16 weeks' amenorrhea for high-risk women, measure and monitor blood pressure at every prenatal visit, screen for proteinuria by urine dipstick or urine protein/creatinine ratio, refer immediately to level 3 obstetrics in cases of suspected severe pre-eclampsia, and provide long-term post-partum cardiovascular follow-up for women who have had pre-eclampsia. Consultations are available at several points of service in Quebec, as well as via telemedicine. To book an appointment, visit cliniqueomicron.ca.
The contents of this page are provided for information purposes only and do not replace the advice of a physician or obstetrician. ACE inhibitors and ARB IIs are formally contraindicated in pregnancy. Preventive aspirin must be started before 16 weeks' gestation to be effective - starting it after 16 weeks' gestation significantly reduces its preventive benefit. Women who have had pre-eclampsia have an increased long-term cardiovascular risk and should be monitored annually.
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