When Zaneta Thayer, an anthropologist at Dartmouth College, asks students in her evolution class what words come to mind when they think of childbirth, almost all of them are negative: pain, screaming, blood, fear.

Then she asks if any of the students has ever seen a woman give birth. Most have not.

Curious about how cultural attitudes and expectations affect the physical experience of childbirth and its outcomes, Dr. Thayer began a study to assess the prevalence of tokophobia, the medical term for a pathological fear of childbirth.

Though tokophobia has been well studied in Scandinavian countries, some of which screen pregnant women and offer treatment for it, little research has been done in the United States. Dr. Thayer’s online survey of nearly 1,800 American women found that in the early days of the pandemic, tokophobia may have affected the majority of American women: 62 percent of pregnant respondents reported high levels of fear and worry about childbirth.

The results were published last month in the journal Evolution, Medicine, and Public Health.

Other scientists who study childbirth said the levels of fear in the United States were higher than those reported in Europe and Australia, which are lower than 20 percent. But they noted that birthing conditions in the United States are different and that pandemic circumstances may have exacerbated fears.