Low salt intake in pregnancy is unlikely to prevent pre-eclampsia.
Pre-eclampsia is a serious complication of pregnancy associated with poor health, or even death, for the mother and baby. Pre-eclampsia is identified by raised blood pressure and protein in the urine during the second half of pregnancy. In the past, a low-salt diet was often recommended, in the belief that it would help to prevent pre-eclampsia. However, the review found just two trials that did not show any evidence of benefit for the mother or baby. Salt intake in pregnancy should be a matter of personal preference. —Cochrane 2012