At the beginning of Toldos the Torah relates that Yitzchak has married Rivka "bas Besuel haArami achos Lavan" and they have no children. Rashi explains that the Torah recounts Rivka's lineage to emphasize that in spite of growing up around a wicked father, a wicked brother, and in a neighborhood of evildoers, she rose above it all and became righteous. Why does this praise belong here at the opening of Toldos?
Later, Rivka is troubled by the pounding she feels in her womb. The Midrash explains what troubled her: When she passed a house of idolatry she felt the kicking of Eisav to get out; when she passed a beis medrash, she felt the kicking of Ya'akov to get out. Meforshim are bothered by this description. Chazal (Nidah 30) tell us that while a baby is in the womb it is taught the entire Torah by an angel. We can easily understand why Eisav would want out of such an environment, but why would Ya'akov be trying to get out? One of the answers given is that even with an angel doing the teaching, Torah cannot be learned properly or appreciated sitting next to an Eisav.
With this in mind perhaps we can answer our original question. The praise of Rivka for rising above the influence of her father, brother, and neighbors is (perhaps) a precursor to the parsha that follows. Why was Rivka so confused at the struggle in her womb? Because she understood why Eisav wanted to get out, but she could not understand why Ya'akov was kicking. If she could spiritually flourish surrounded by negative role models, why was Ya'akov, who was learning Torah from an angel, so anxious to get out just because his neighbor was Eisav?
For another insightful comment on the parsha, see my wife's blog here.