During pregnancy, women experience increased demands for certain nutrients to support the growth and development of the fetus. Two essential nutrients that are commonly deficient in pregnant women are calcium and iron.

Calcium is necessary for the formation of the baby`s bones and teeth, as well as for the proper functioning of the mother`s muscles and nerves. Iron is crucial for the production of red blood cells, which transport oxygen to both the mother and the developing baby.

While sodium is an essential mineral, it is not typically associated with deficiency in pregnant women. It is important to note that each woman`s nutritional needs may vary, so it is crucial to consult with a healthcare professional to determine specific dietary requirements during pregnancy.

In conclusion, option 3 - calcium and iron - is the correct answer as these are the nutrients that pregnant women often become deficient in.