If it's causing her pain, then you need to do something about it. Both my girls were infrequent poopers, and for both it was a problem (painful, gassy, etc.).
Make sure you are drinking enough water. That really helped with dd2. We get so busy that it's easy to forget, so start chugging!
Another thing you can do is rub some castor oil on her tummy, and this may help her move her bowels.
I second the chiropractic adjustment and craniosacral work (you can search for a cs therapist
here).
Another thing that helped us tremendously was homeopathy, but not until we saw a trained homeopath (also an intuitive healer). I never have much luck with the Hylands, etc., stuff I get at Whole Foods.
You can also give probiotics. All of the care providers we've seen recommend the HMF brand, you would use Natogen for a baby (you can get it through the website of the holistic ped we've seen
here). I just lick my finger, dip it in the powder and put it directly in her mouth. Try once or twice a day and see how it goes.
It's possible it could be something in your diet. I did
total elimination diets with both my girls (for a variety of reasons - gas, reflux, etc.). They suck royally. Didn't help dd1. It did help dd2 with her reflux, but nothing else (gas, burping, infrequent poops, etc.).
When dd1 was older and on solids, I would give her pureed prunes (Earth's Best brand, mixed with oatmeal), and I think that helped too. But I think ideally you want to correct the underlying digestive issue, so things like bodywork, homeopathy, probiotics will take you in that direction.
Good luck!