This is also a sign that her period is imminent. Be sure to not rely on this symptom as the only indicator of pregnancy. A pregnant woman's body is going through the most changes she will ever endure. Just imagine what a growing bowling ball would feel like inside your pelvis and then try to fathom what it must feel like to pass it out through your butt. That might give you a vague idea of how it feels to give birth.
Extreme fatigue is common especially early on.
Her body is working extremely hard to reorganize and prioritize and as a result, while she may be doing everything visibly as she normally does, she's wasted after a day on the job and wants to do nothing but sleep. Scents and smells she used to love may now send her flying to the bathroom to place a collect call to Uncle Ralph. At the same time, she may begin craving strange things to eat. Better have them on hand or you may find yourself driving to the nearby convenience store. A missed period, however, is your biggest single clue that something is cooking inside her.