When people picture pregnancy, they often imagine a fairly predictable sequence of events: a positive test, a first ultrasound, a growing bump and, eventually, a baby.
But according to anthropologist Kate Clancy, that narrative leaves out a reality that has shaped human reproduction for millennia.
In her new book, Pregnancy Interrupted: The Science and Stories of How Pregnancies Really End, the University of Illinois Urbana-Champaign professor argues that pregnancy loss may in fact be the most common outcome.
“The biggest issue is that we frame [a full-term pregnancy] as the normative experience,” Clancy told Newsweek. “And that anything that doesn’t follow that is the deviation.”
Instead, she believes a more productive way to think about pregnancy is to understand that losses at various stages are not exceptions to the rule but part of how human reproduction often works.
The book explores pregnancy as a complex biological process involving a series of developmental checkpoints.
Before a pregnancy can progress, eggs, embryos and the reproductive system must repeatedly pass what Clancy describes as tests of viability.
Those tests begin long before most people realize they are pregnant.
“The type of reproduction we do is basically throw spaghetti at the wall,” Clancy said. “So that means we make tons of eggs. Most of them are garbage.”
Even after fertilization, many embryos never continue developing. Some fail shortly after implantation. Others stop developing weeks later because of chromosomal abnormalities or other biological factors.
For Clancy, one of the most surprising discoveries during the research process was learning how resilient embryos can be.
Scientists have found that some embryos can effectively “self-correct” genetic mistakes during early development.
Cells carrying chromosomal errors may be pushed into tissue that later becomes the placenta, while healthier cells continue developing into the fetus.
“It made me think differently about testing, and about the ways that we predict how a baby’s going to turn out by what we can see on their embryo, or what we can see from pre-implantation testing or not pre-implantation testing,” Clancy said.
Not Your Fault
Many people who experience miscarriage blame themselves, even when science suggests they shouldn’t.
Clancy said one of her goals was to help readers understand how little control individuals often have over pregnancy loss.
“The first half of the book is on the science of pregnancy and it really shows you how inevitable a large percentage of pregnancy loss is,” Clancy said. “Unfortunately, lots of [embryos] were never going make it, no matter what that person did.”
While some factors can increase risk, they are often environmental or structural rather than the result of personal choices.
Clancy points to infectious diseases, environmental pollutants, endocrine-disrupting chemicals, and experiences such as intimate partner violence as examples of factors associated with adverse pregnancy outcomes.
“It really has a lot more to do with, what is the government support towards food safety and around public health? What kind of regulations do we have to keep endocrine-disrupting chemicals out of our food? It’s about what the government does or doesn’t do to protect the population.”
That perspective may offer comfort to people who have experienced pregnancy loss and spent years wondering whether they could have prevented it.
“The two big drivers are biology and environment,” Clancy said. “Not individual choices.”
Rethinking Pregnancy
The book also challenges another influential idea: that pregnancy is fundamentally a struggle between mother and fetus.
In evolutionary biology, this concept is sometimes referred to as “maternal-fetal conflict,” the notion that the interests of the pregnant person and the developing fetus are often at odds.
That framing has filtered beyond academia and into everyday language, Clancy said.
“People joke a lot about, ‘I’ve got a parasite eating me,'” she said. Others describe themselves as a “short-term rental” or compare a fetus to a tenant they cannot wait to evict.
“There’s this oppositional language that people use when describing pregnancy,” Clancy said. “The science is much more cooperative. There are ways in which each is invested in the other’s survival.”
That shift in perspective is one of the key takeaways she hopes readers will gain from the book.
While carrying out research, Clancy interviewed many people who had experienced miscarriage, and a recurring theme was how often they went through it alone.
“The main thing is to come away with a bigger understanding of what is often a private, quiet, lonesome process,” she said.