put a little dark karo syrup in her bottle. Thats what every doctor my children have been to have said and it worked for them.
try pears or pear juice. We would give 2 oz of pear juice in with 6 oz of milk for an 8 oz bottle and my son was regular with this help. We'd also give pears - the Gerber stage 3 food in a jar or whatever stage your baby is eating. Gerber makes a prune baby food too - even apple/prune that my son liked. But try the pear juice. When my son was 4 mos we had to use a gylcerine suppository (uppont he recommendation of our pediatrician) - those work too. Good luck.
Any fruit juice will help with getting fluids to the area. You can mix the prune juice and pear juice if needed also. The gas will come then she will feel better after she goes good. until she goes make sure she has lots of soft foods and no meat or breads till she goes, including pasta. Fiber makes it worse on babies.
add a little karo to her bottle/water, or some milicon gas drops should do the trick!