Loaded with folate, potassium, vitamin C and vitamin B6 (which helps baby's tissue and brain growth as well as eases morning sickness), avocados are a delicious way to get your vitamins. Spread some ripe avocado on your whole grain roll as a healthy substitute for mayo.
Tip: Keep in mind that avocados are high in fat (though the very good kind) and calories, which makes them filling — but be careful not to overdo it unless you're having trouble gaining weight.