ABSTRACT
A geographically population-based epidemiological study was conducted in Thailand under the WHO International Collaborative Study of Hypertensive Disorders of Pregnancy. Prospectively collected data on blood pressure, proteinuria and edema in pregnancy of 4,126 pregnancies were analyzed correlating with pregnancy outcome. The prevalence of mothers with antenatal diastolic pressures equal to or greater than 90 mmHg was approximately 20 per cent. Hypertension with edema or proteinuria was observed in about 6 per cent of pregnancies and these were associated with a significant increase of low birthweight infants, but did not produce a significant increase in perinatal deaths. Although the incidence of eclampsia during the study period was not high, Hypertensive Disorders of Pregnancy remained the second leading cause of maternal mortality.