Definitions
PE was defined by the presence of de novo hypertension (systolic blood pressure (BP) > 140 mmHg and/or diastolic BP> 90 mmHg measured on two occasions at least 4 hours apart) after 20 weeks of gestation accompanied by proteinuria (> 300 mg/24h or a urine protein/creatinine ratio > 0.3 mg/mmol)(20). Early-onset cases were considered when admission occurred before 34 weeks of gestation. Gestational age was calculated according to the crown-rump length at first-trimester ultrasound scan (21). Severe features were defined according the American College of Obstetricians and Gynecologists as: systolic BP> 160 mmHg or diastolic BP > 110 mmHg on two occasions at least 4 hours apart, thrombocytopenia (<100x109/L platelets), impaired liver function (blood concentrations of liver enzymes to twice normal and/or severe persistent right upper quadrant or epigastric pain unresponsive to medication and not accounted for by alternative diagnoses), renal insufficiency (serum creatinine concentration greater than 1.1 mg/dl in absence of other renal disease), pulmonary edema or new-onset cerebral or visual disturbances (22).
At admission, the risk for complications was estimated according to the Prediction of complications in Early-onset-Preeclampsia (PREP-L) score (12,23), which includes maternal age, gestational age, preexisting medical conditions, protein-to-creatinine ratio, serum urea concentration, platelet count, systolic blood pressure, need for antihypertensive treatment or magnesium sulphate.
Maternal complications were defined as: (i) HELLP syndrome (lactate dehydrogenase [LDH] >600 IU/L, AST to twice normal values and platelet count <100x109/L); (ii) Central nervous system dysfunction (eclampsia, Glasgow Coma Score <13 (24), stroke, reversible ischemic neurological deficit or cortical blindness); (iii) hepatic dysfunction (INR >1.2 in the absence of disseminated intravascular coagulation, MELD score> 10 (25,26) or hepatic hematoma or rupture); (iv) renal dysfunction (dialysis, serum creatinine concentration greater than 150 µmol/L or urine output <0.5 ml/kg/h during 12 hours, according to renal insufficiency by RIFLE criteria (27); or need for treatment with furosemide to maintain urine output >0.5ml/kg/h for 3 hours); (v) respiratory dysfunction (pulmonary edema, requirement of invasive or non-invasive mechanical ventilation, oxygen requirement greater than 50% concentration for longer than 1 hour or severe breathing difficulty [no criteria of pulmonary edema but presence of dyspnea, crackles in pulmonary auscultation and SaO2<90%]); and/or (vi) cardiovascular dysfunction (need for inotropic support, left ventricle failure or myocardial infarction); (vii) critical hypertension (requirement for three or more different antihypertensive treatments to control BP).
Fetal growth restriction (FGR) was defined according to the Delphi consensus for early-onset form (28).