Outcome measures
Outcome measures were delivery with PE or GH. Data on pregnancy outcome were collected from the hospital maternity records or the general medical practitioners of the women. The obstetric records of all women with chronic hypertension or pregnancy associated hypertension were examined to determine the diagnosis of PE or GH. Diagnosis of GH was based on the finding of hypertension (systolic blood pressure of> 140 mm Hg or diastolic blood pressure of> 90 mmHg on at least two occasions four hours apart developing after 20 weeks’ gestation in previously normotensive women). Diagnosis of PE was based on the finding of new onset hypertension or chronic hypertension and at least one of the following: proteinuria (≥300 mg/24h or protein to creatinine ratio > 30 mg/mmoL or > 2 + on dipstick testing), renal insufficiency with serum creatinine >97 µmol/L in the absence of underlying renal disease, hepatic dysfunction with blood concentration of transaminases more than twice the upper limit of normal (≥65 IU/L for our laboratory), thrombocytopenia (platelet count <100,000/µL), neurological complications (e.g. cerebral or visual symptoms), or pulmonary edema.28