Jezebel (linked above) explains pregnant women’s legal bind: “Employers can fire, lay off and refuse to hire knocked up ladies, but they have to provide ample proof that they held men to the same standards. They also have to provide maternity leave, as they would provide leave for any other medical issue, but in 48 of the 50 states, that leave doesn’t have to be paid (readers in California and Washington State, you’re the lucky ones).”
That’s pretty much right. There is a Pregnancy Discrimination Act, but it’s protections are limited. And it doesn’t require affirmative protections for pregnant women but rather restrains companies from treating pregnant women worse than men and women who are not pregnant. In fact, the Supreme has specifically rejected any requirement of affirmative protections for pregnant women.
Of course, this all goes to the point that we live in a society that doesn’t really care about having women as equal citizens, or really about children and even fetuses (except when they can be used as political pawns). Call me crazy, but I’d argue that firing a woman or treating her badly during her pregnancy is certainly not the way to assure a healthy pregnancy and birth.