Constipation is a common problem for pregnant women, but one remedy may be a nondigestible type of fiber naturally found in fruit and vegetables. Japanese scientists saw improvement in 29 moms-to-be who were given supplements of xylooligosaccharides (XOS). "XOS is a type of fiber that our bodies cannot digest, but it turns out to be food for a type of 'friendly' bacteria in our gut," says American Dietetic Association spokeswoman Melinda Johnson, R.D. "Eating foods containing XOS or taking a supplement with XOS seems to promote a healthy intestine." She recommends that women aim for 25 grams of fiber a day from fruits, vegetables and whole grains.