Despite the widespread media coverage of the undercover videos exposing Planned Parenthood's alleged sale of foetal baby parts that instigated congressional and state investigations in the United States, the reaction of most Americans is, "What videos?"

The Center for Medical Progress (CMP) released the videos that purportedly show Planned Parenthood officials discussing and negotiating possible payments for donated foetal remains, which the abortion provider denied.

But a phone survey of 1,000 Americans by Lifeway Research showed that 7 out of 10 are either not aware of the videos (43 percent) or have not spoken out after seeing them (27 percent).

Among those who are aware of the videos, relatively few spoke out against Planned Parenthood, the researchers said.

"Given the serious accusations against Planned Parenthood—that they sold baby parts—it is surprising how few Americans responded," said Ed Stetzer, executive director of LifeWay Research.

The survey was completed last September during which the videos received widespread attention among Republican presidential candidates.

The survey showed that overall, 1 in 5 (18 percent) Americans spoke out against Planned Parenthood after the videos were released and 1 in 8 (12 percent) supported Planned Parenthood.

In responding to the videos, two-thirds either didn't say anything or supported the abortion provider. Only about a third spoke out against Planned Parenthood.

"The videos caught many people's attention, even prompting Hilary Clinton to call them disturbing, yet Americans remain quite divided on abortion," said Stetzer. "That division appears to be reflected even in their views on such videos."

The survey found out that religion played a role in how Americans responded to the videos.

Those who are evangelicals (29 percent) and Christians (32 percent) are more likely to have criticised the abortion provider while 17 percent of non-religious are more likely to have supported Planned Parenthood.

A total 27 percent of those with evangelical beliefs and 27 percent of weekly churchgoers are more likely to speak out against Planned Parenthood than other Americans.

Across racial and ethnic groups, 1 in 3 whites (32 percent) are unaware of the videos. More than 6 of 10 African Americans (60 percent), Hispanics (66 percent) and people of other ethnicities (61 percent) do not know about them.

The survey also showed that Americans over 65 years of age (25 percent) are more likely to have spoken out against Planned Parenthood than those 18 to 24 years old (7 percent).

Also, Americans who are 18 to 24 (18 percent) years of age are more likely to have supported Planned Parenthood than those who are 25 to 34 (9 percent), 35 to 44 (5 percent) or 55 to 64 (9 percent).

Stetzer said the reaction to the videos may provide a lesson to pro-life groups.

"Through social media it is easy to assume everyone in America is having the same conversation," Stetzer said. "But these results show that is not the case."