Having seen Kill Bill 2, and just to play Devil's Advocate and support Brooke's side to some extent-

The exact scene she is referring to, I believe, has more weight in the CHARACTER'S value of a possible child and of being a mother than in the assassin placing more value in her life because she's now pregnant. One of the major points of Kill Bill 2 (moreso than the first) is about how The Bride felt about her child, about losing her child, about WANTING to be a mother, and about wanting to protect her child. I think it IS fair to say that when a woman become pregnant and has either planned to or decides she wants to carry the pregnancy to term and then become a mother, that she may start putting a lot more value in her own life, for the sake of the fetus and future child than she would have before.

The scene in the movie, the way I saw it, was a lot more The Bride pleading with her assassin to not kill her, and that had a lot to do with the fact that WHEN she found out she was pregnant (you find this out later in the movie), not only did she want to be able to keep the pregnancy and protect it, but because from that moment she wanted to END her life as an assassin for the sake of her future child, and to escape that life and Bill so her child would not be affected by that.

(However, as an afterthought, I would be willing to bet the fact the other assassin was a woman has more to do with why that scene isn't flat-out-offensively sexist, but DOES point to a number of reasons WHY there ARE still issues of sexism IN the film. And, having seen the film, I DO think that Beppie has made a strong argument in the fact that the whole scene DOES still present the other woman respect the Bride's pleads BECAUSE she was pregnant.)

I feel like I'm rambling so I'll cut it there, but in the short-of-it, I think both arguments have reasonable ground.