I never examined how they looked pre/post baby (maybe except for Charisma, since she did post for Playboy after she had her son) but you have to remember that you can't compare them to a normal, average, everyday mom. They have major help: nannies, cooks, trainers, cleaning people, etc. I don't really care how Hollywood women look during or after pregnancy. I care more about the fact that many women in this country lack prenatal care, that the cesarean rate has been climbing for the past 20 years & is now at 34%, that among industrialized nations we have one of the highest maternal mortality rates. I care more that African-American baby boys have higher infant mortality rates than any other group, that many women are treated as merely cogs in the machine of medicalized birth & have few real choices. I care that our society is super-happy about boobies! unless there's a baby attached and that maternity leave policies in the US are so lacking. I care about a poor woman's access to career training & higher education do that she can break the cycle of poverty, & I care that her children can receive high quality early childhood education.
I admire SMG, Alyson, & Charisma as actors. I don't know them personally though & I could care less about their pre/post pregnancy appearance.