As is indicated in this article, the role of healthy bacteria, or healthy flora may actually begin in utero. This suggests that mothers-to-be or women thinking about getting pregnant may want to start addressing their own gut flora now in order to insure healthy flora in their offspring. Healthy flora helps build a strong digestion and a strong immune system, which helps prevent colic, allergies, eczema and asthma in infants.
I have always advocated that expecting mothers start the process as soon as possible of making sure their gut flora is as healthy as possible. You can do this by taking a good quality multi-strain probiotic, and avoiding processed food, such as simple carbs and sweets. For further recommendations on a healthy diet for establishing healthy gut flora see my link to The Modified Yeast Free Diet.