Salt intake, home blood pressure, and perinatal outcome in pregnant women

Background: The relationship between salt (sodium chloride) intake and pregnancy-induced hypertension (PIH) remains unclear. The aim of this study was therefore to investigate the current status of salt intake during pregnancy and identify effective predictors for PIH. Methods and Results: Participants were 184 pregnant women who collected 24-h home urine as well as early morning urine samples. We investigated urinary salt excretion, home blood pressure (HBP) measurements for 7 consecutive days before the 20th and after the 30th gestational week, and the development of PIH. Urinary salt excretion according to early morning urine before the 20th gestational week was 8.6±1.7 g/day, and was significantly correlated with that measured from 24-h collected urine. Early morning urine estimated urinary salt excretion was slightly but significantly increased during pregnancy. HBP was 102±10/63±8 mmHg before the 20th gestational week and 104±12/64±10 mmHg after the 30th gestational week. On multiple regression analysis, serum uric acid and body mass index, but not urinary salt excretion, contributed to HBP both before the 20th and after the 30th gestational week. Fourteen participants (7.6%) developed PIH. On multivariate analysis, higher HBP and older age, but not urinary salt excretion, were significantly associated with PIH. Conclusions: Higher HBP and older age, but not urinary salt excretion, are predictors of PIH.