Those expectant moms have the support of some Democratic lawmakers who have tried for years to ban BPA from children's products. There are studies that support both sides, leaving some to wonder which way to vote.
These expectant moms are running out of time in their fight against the powerful chemical industry.
They're pushing to get bisphenol-A (BPA) banned from use in the plastics of baby bottles, sippy cups and formula-can liners.
"It's a David and Goliath fight," said expectant mother Melissa Walthers. "I think at the end of the day, our legislators should be making decisions that protect children over anything else."
The fight was tough in the Assembly. The sponsor of the bill, state Sen. Fran Pavley (D-Santa Monica), spoke to undecided lawmakers citing more than 200 studies linking BPA to health issues like cancers and neurological problems.
"I think most would err on the side of precaution when it comes to young children and pregnant women," said Pavley.
But the American Chemistry Council, which last year spent more than $5 million influencing Sacramento, cited even more studies.
"The collective data from international scientific bodies has concluded that BPA is safe as used," said Tim Shestek, senior director of the American Chemistry Council. "Again, this is a political decision, not something that's being made by scientific fact."
Opponents of the ban also point out parents can already buy BPA-free baby products. But they're not available in all stores, especially in poor neighborhoods.
"It shouldn't be my job to determine what's safe and what's not," said Gretchen Lee Salters, an expectant mom. "I shouldn't have to be a chemist or toxicologist to go to the grocery store and know what I'm buying is safe."
The Food and Drug Administration does share some concern about the potential effects of BPA and recently began studying it, but supporters of the California ban don't want to wait.
In the end, the bill fell four votes short. Pavley has until the end of August to find them in order for the bill to stay alive.