J.L.
My son is 5 weeks old and seems to get hiccups all the time, but it appears to be less related to gas and more related to him getting overstimulated. For instance, if he starts struggling to poop after he eats, he'll get the hiccups.
Also, my Dr. told me that if he got the hiccups a lot in the womb, he'll probably get them a lot still and that it's nothing to worry about.
Hope this helps. :)