Other Nutrients
There is very limited information on molybdenum during pregnancy; most studies will combine research aspects with other metals such as selenium and zinc. Supplementation of molybdenum is not recommended during pregnancy, especially since deficiency appears to be rare.
Phosphorus levels do not change and are not affected during pregnancy; therefore, supplementation is not necessary. Phosphorus is found in a wide variety of foods and deficiency is incredibly rare.
Background
Molybdenum is an essential trace element for virtually all life forms; its main function is to remove toxins from the body.
Phosphorus is the second most abundant inorganic element in the body. It is necessary for the structural component of cell membranes and for bone mineralization (to include for the fetus).
Pregnancy
There is no direct data available to determine any additional daily requirement for molybdenum during pregnancy and information is limited because of lack of a simple method for determining amounts of molybdenum in the body. However, recommendations have been set at 50 micrograms (mcg)/day.
There are no increased requirements for phosphorus during pregnancy and levels do not appear to be affected by pregnancy at any stage. Recommended daily phosphorus intake during pregnancy is the same amount set for non-pregnant individuals, at 700 milligrams (mg)/day with an upper intake level set at 4,000 mg/day.
Phosphorus is so common in the food supply that deficiency is extremely rare, but results in symptoms which include muscle weakness, bone pain, rickets, increased susceptibility to infection and anemia.
Aluminum-containing antacids (common medications during pregnancy) can decrease phosphorus levels in the blood, especially when taken at high doses. However, the amount of antacids women may take during pregnancy should not make this a concern.
Food Sources
Molybdenum is found in plant foods and the amount in each food depends on the soil content. Legumes, beans, nuts, and grain products are major sources of molybdenum in the western diet; animal foods, fruits and vegetables are low in molybdenum.
Dairy foods, cereal products, meat, fish, oat bran, lentils, and soy products are good sources of phosphorus in the diet, as well as most other foods. Phosphorus is also in soft drinks as phosphoric acid.
Resources
Phosphorus Fact Sheet (Oregon State University, Micronutrient Information Center)
Molybdenum Fact Sheet (U.S. National Institutes of Health, Office of Dietary Supplements)