Greenie, women react so individually to pregnancy that it could be almost anything. 50% of women never suffer morning sickness, but among the 50% of us that do, some of us are sick all day long for months on end. Some women's breasts respond quickly to the extra hormones; some women's waists do, so size change will depend on the woman.
You didn't mention whether the woman knew she was pregnant or not. If she did, she might be changing her own behavior (e.g. a heavy coffee drinker might suddenly switch to decaf). The easiest way to tell, of course, is the "classic" pregnancy symptom of morning sickness: sick every morning, can't face coffee or food first thing, starts feeling better about mid-day and can handle something light, ravenous at dinner time.
