Our body excretes almost as much iodine as it takes in under conditions of adequate and stable iodine supply, so if a pregnant mother’s urinary iodine value is low, it is a sign that she is not taking enough iodine. Iodine is a very important mineral needed by the human body. Insufficient iodine intake by pregnant mothers may lead to growth retardation, mental retardation and even cretinism in severe cases. Therefore, during pregnancy, we need to clarify the presence of iodine deficiency in pregnant mothers through a urine iodine test. A single urine should be determined using the ratio of urinary iodine to urinary creatinine, while the test for urinary iodine alone should be performed using a 24-hour urine test. If the urine iodine is below 150 μg/L, it indicates that the pregnant mother is not receiving enough iodine. The Chinese Nutrition Society recommends that seaweed vegetables should be supplemented 1-2 times a week during pregnancy, which can be a good way to help pregnant mothers replenish their iodine.