You’ve heard the recommendation before: Cut salt for the sake of your blood pressure. You may have even heard this low-salt mantra while pregnant. Out of fear of high blood pressure, salt has been demonized for decades on the presumption that it causes hypertension. One problem: The rules are different for pregnant women.
If You're Pregnant Or Trying, Don't Skimp On This Key Mineral
Low-salt recommendations may be harmful to pregnant women.
Numerous studies suggest that low-salt diets in pregnancy may be harmful to the mother. Indeed, pre-eclampsia—pregnancy complications attributed to high blood pressure—has been suggested to be a state of salt depletion due to inappropriate release of a salt-retaining hormone called aldosterone. Eating more salt may help formerly pre-eclamptic women from transitioning into hypertension by improving low plasma volume. Blood volume is reduced in pre-eclampsia, which may explain why eating more salt has been found to help prevent and treat pre-eclampsia in a study of over 2,000 pregnant women.
Another article studying the importance of salt in pregnant women pointed out the difference between recommendations for the general population and pregnant women specifically. "Our data support the importance of salt in normal pregnancy, a critical issue given the passionate campaigns to lower salt intake in the general population…Providing salt administration could be an option to avoid pathological pregnancy conditions such as pre-eclampsia, a cheap and easy intervention particularly important in low resource settings."
Salt deficiencies can cause harm to mother and baby.
Additionally, the requirement for iodine can increase by 50 percent or more during pregnancy. The World Health Organization recommends that pregnant women consume 250 mcg/day of iodine. However, they also recommend cutting salt intake to less than 5 grams per day. These recommendations contradict each other. If a pregnant woman has a poor intake of iodine, even if all of those 5 grams of salt comes from iodized salt, it still would not provide the recommended amount of iodine per day. (It should be noted that himalayan and sea salt contain small traces of iodine or none at all.) In fact, it would take around 5.6 grams of iodized salt to do this in pregnancy. In other words, it's important for women to talk to their doctors and health care providers about appropriate supplementation and the implications of their salt intake on iodine levels. In contrast, other studies say consuming around 20 grams of salt per day (or about 3½ teaspoons of salt) may be beneficial in pregnancy. Low-salt advice meant for the general population may be putting unborn children at risk of iodine deficiency and all the consequences that can come from it (cognitive and motor dysfunction, hypothyroidism, decreased growth, and even death).
As I discuss in my book The Salt Fix, a comprehensive study of over 2,000 pregnant women showed that a low-salt diet, as compared to a high-salt diet, caused more miscarriages, premature babies (born < 34 weeks' gestation), still births, perinatal and neonatal deaths, edema, toxemia (pre-eclampsia), and bleeding. Thus, for the sake of the mother and her unborn child, it's important to consider and ask your health care provider about your salt intake during pregnancy.