Reply #29: As some have mentioned above, it IS possible.

[BlueIris]

Depending on a lot of things—the woman's size, the size of the fetus, whether the fetus is active or not. And there are ways for a placenta to be positioned so that some women feel very little movement during their pregnancies, even if the fetus is active.

Some women continue to bleed monthly through their entire pregnancies. Some people don't feel Braxton-Hicks contractions (or actual contractions). Some women don't gain very much weight, and some have body types that don't "show" the weight gain or abdominal distortion from the growing fetus even if they do put on the normal amount of pregnancy weight.

But I doubt situations like this are all that common, even in cases in which someone is in total, clinical denial.