Final answer:
A pregnant woman should consume more canned sardines from the list to increase her calcium intake; they are high in calcium, which is essential for both mother and baby during pregnancy.
Step-by-step explanation:
To increase her calcium intake, a pregnant woman whose diet history is under review should be encouraged by the nurse to consume more canned sardines. Among the options provided, canned sardines are particularly high in calcium because they contain soft bones that are edible and rich in this essential nutrient. Calcium is vital during pregnancy not only for the mother's bone health but also for the developing fetus.
Other dietary sources of calcium include dairy products, green leafy vegetables, nuts, beans, seeds, and certain types of shellfish. It's important for a pregnant woman to consume adequate amounts of nutrients to support both her own health and the growth and development of her baby.