For mothers-to-be, that baby heartbeat is a sign of sweet things to come. For the medical community, it's a force not to be reckoned with or researched.
"If anything happens to that baby, it could be blamed on whatever that research protocol was," said Dr. Aaron Caughey, UCSF.
As a result: there isn't much hard data available on pregnant women - like drug interactions and the effects of medical procedures on the fetus.
"They don't get the recommended standard of care treatment, the gold standard treatment that you would normally provide for a non-pregnant woman, and yeah, we see that all the time," said Dr. Caughey.
The FDA has only approved a dozen medications for use during pregnancy. That means, any other medications used during pregnancy, from diabetes to depression, are used without approval from the FDA.
"When you're pregnant nothing's simple," said Rowena Tarantino, expectant mother.
"Sometimes they let the choice be mine and they sort of give you the research that's out there, I mean it would be nice if there was more," Anita Krpata, expectant mother.
"The guessing game is difficult," said Karla Gil, expectant mother.
But for an expectant mother, being a part of a research study can be a bit taboo.
"I certainly wouldn't be the first in line to be tested," said Tarantino.
"Obviously there's a certain amount of risk involved when you participate in any kind of research study," said Gil.
"I would be interested, but I also am concerned about the safety of the baby, so I understand why it's a difficult topic," said Krpata.
And even if they are interested, doctor and economist Aaron Caughey says: there isn't much incentive for researchers.
"You have one bad outcome and gees, yes you demonstrated the effect but found this horrible thing, and it may or may not be associated, but it doesn't make a lot of economic sense if you're a drug company," said Dr. Caughey.
We checked with the organization: Pharmaceutical Research and Manufacturers of America and here's what they had to say: "Obviously, for ethical reasons, you cannot include pregnant women in clinical trials. What's more, it is very difficult to obtain permission from ethics boards to conduct such trials."
Dr. Caughey says: it needs to start with a public push.
"You start having bigger populations and those people will ask questions and push the agenda, they will make their doctors ask the questions and push the agenda," said Dr. Caughey.