Abortion has been federal law in America for over 40 years, yet every election cycle politicians in Democratic Congressional districts campaign on the issue - and sociologists write about this common medical procedure. How common? So common it happens more often than miscarriages, according to a new paper.

Surveys are not telling us much new at this point but a sociologist writing in Sociological Science analyzes a survey and finds that anti-abortion people are less likely to hear about the abortions women they know have had than are pro-abortion Americans.

That makes obvious sense.  A miscarriage is exculpatory, it happens to women, while abortions are done by choice, and so it is less socially acceptable, especially if it is a controversial late-term one. The finding was culled from a nationally representative survey of more than 1,600 American adults who reported on their knowledge of others' and their own experiences (or their partner's experiences) of abortion and miscarriage. The author believes they have controlled for confounding variables and say it affirms that Americans who are against abortion are much less likely to hear of others' abortions than Americans who are for it. Specifically, those who believe abortion should be legal under no circumstance are 21 percent less likely to have heard about another having an abortion than are those who believe abortion should be generally available. 

Where did the survey even find Americans who think it should never be allowed? Those are rare. Instead, most Americans want abortions to be curtailed. The US and Canada are the only two developed nations that allow late-term abortions on demand, other countries have restrictions. 

The author also found that those who believe abortion should be legal only in the cases of rape, incest, or to save the life of the pregnant woman are 12 percent less likely to have heard about another having an abortion than are those who believe abortion should be generally available. 

"Americans who are opposed to abortion are less likely to hear that their sister, mother, or friend had an abortion than their pro-choice peers," says Sarah K. Cowan, an assistant professor in sociology at New York University, a Robert Wood Johnson Foundation Health and Society Scholar at Columbia University, and the study's author. "Abortions are often kept secret both by women who have had them and by their confidantes. Moreover, abortions are especially likely to be kept secret from those who are pro-life. These disclosure differences affect who hears about others' abortions and may help explain the relative stability of Americans' opinions on abortion."  

Cowan believes believes her method reduced the likelihood that the results merely reflect association differences among groups—that is, pro-life Americans are less likely to say they know someone who has had an abortion because they tend to associate with those who are less likely to undergo this procedure. 

The research does so by controlling for a range of characteristics that could reveal such associative differences—these include race, age, religion, political party affiliation, and religious service attendance among others. Even after taking these into account, there exists a substantial difference in the likelihood of hearing an abortion secret by one's attitude toward abortion.

The findings also vary notably from those pertaining to miscarriages, though that could be because miscarriages are more known about now - with early pregnancy tests a miscarriage that was once just a missed period or two can now be known to be a miscarriage. 77 percent of women and their partners who experienced a miscarriage tell someone else; for each miscarriage they tell, on average, 2.63 people. 66 percent go on to share their abortion story to an average of 1.24 people. 

Since abortions are tracked and miscarriage often isn't, abortions are more common. Cowan says that almost 33% of American women will have an abortion in her lifetime yet more Americans have heard of another's miscarriage than abortion – 79 percent have heard of a miscarriage and 52 percent of an abortion. This discrepancy arises from differences in disclosure.  

"A third of women who have had an abortion have kept it a secret from someone with whom they usually talk about personal matters," explains Cowan. "In addition, one quarter of confidantes also keep the secret. Abortions are predominantly kept secret from immediate family members. People keep abortions – their own and others' -- a secret for reasons of privacy and to protect the woman who had the abortion from stigma."