From what I've been told, constipation is common during pregnancy because your digestion slows to allow you to absorb more nutrients. Later on (late 2nd trimester +) there will also be crowding of your intestines. I'm sorry to say that it will likely get a lot worse before delivery.
The best advice I know is eat healthy easily digestible foods (whole foods, high fiber), drink plenty of water (8-10 cups a day - at least 80 oz), and exercise at least 30 minutes a day. All of this will keep things moving the best they can. I find water, diet, and exercise completely takes care of any gastric issues I have had.
Re: Hi