Traditional hiccups are (traditionally) an involuntary spasm of the diaphragm. The sudden rush of air into the lungs causes the glottis to close, creating the "hic" noise. They are also, traditionally, felt in one's throat or chest.

Fetal hiccups, however, are felt in your big round stomach, and unlike traditional hiccups, cannot be cured by offering the sufferer a glass of water. It is also very difficult to frighten the hiccups out of the sufferer, as fetuses pay little attention to world politics and seem unimpressed by the distressing rise of medical fees and university tuition.

-hic!-