Correction: An earlier version of this story mistakenly stated that the total rate of miscarriages could be as high as 80 percent.

Last week, the Georgia legislature passed HB 481, a bill that defines an unborn child as a “living, distinct person” entitled to “full legal recognition.”

Under this law, not only will abortions be treated as murders, but miscarriages will be subject to criminal investigation, as they already are in a number of states. As many commentators have pointed out, this bill and others like it that grant “personhood” to fetuses display a profound ignorance of the biology of reproduction. Nearly 15 percent of recognized pregnancies end in miscarriage — a conservative estimate. The total rate of miscarriages may be as high as 50 percent.

But if the sponsors of these bills are willfully obtuse about female physiology, they stand squarely within a very long history in western medical thought of regarding the womb as a dangerous place and imagining fetuses as in dire need of protection from the women who carry them. It's that very thinking that we must overturn, relying instead on science and offering support and understanding, not suspicion and investigation, for women who miscarry.

The idea that the womb is a dangerous place might seem counterintuitive. After all, for much of western history, embryos and fetuses could not survive anywhere but the womb. And even in the age of in vitro fertilization and state-of-the-art neonatal intensive care units, the womb has not been replaced as the site of gestation. Despite this fact, however, in a great deal of medical writing on pregnancy for the last 2000 years, the womb has not been imagined as a warm, safe and comfortable home. Wombs — and women’s bodies more generally — have been seen as hostile environments.

From the time of Hippocrates in ancient Greece, medical writers accepted that fetuses were nourished in the womb by their mothers’ blood. However, this blood was frequently equated with menstrual blood, which was toxic. This lent a peculiar ambivalence to the pregnant body, because it both nourished and poisoned.

In the 10th century, the Persian physician 'Ali ibn al-'Abbas al-Majusi (known in Europe by his Latinized name, Haly Abbas) posited that smallpox, an endemic disease that afflicted a high percentage of children, was caused by menstrual blood. In the womb, he claimed, the fetus absorbed the mother’s menstrual blood, which was toxic. After birth, this poison remained in the child’s bloodstream. The fevers, pain, rashes and pustules of smallpox were the body’s efforts to purge menstrual toxins from the body. Some children survived this purging and emerged healthier with purified blood; others succumbed to the poison.

Haly Abbas’s explanation of smallpox became the dominant explanation of this very common disease in the Arabic-speaking world, and later, in Latin translation, in Europe. For nearly a thousand years medical opinion in the Middle East and Europe held that all mothers poisoned the fetuses they carried. Part of growing up was overcoming this maternal taint.

Another medical doctrine that was virtually unquestioned until the 19th century was the notion of maternal imagination. Almost all pre-modern medical writers agreed that mothers’ minds had the power to shape their fetuses in utero. Anything that made a strong impression on a pregnant woman, especially if it was frightening or repulsive, might leave an imprint on the fetus. All kinds of birthmarks and abnormalities were blamed on maternal imagination. Babies were born with “hare-lips,” for example, because their mothers had been startled by rabbits while they were pregnant.

Both popular and medical literature abounded with stories of babies born deformed in various ways because of maternal imagination — like the baby born with hair all over its body because its mother looked at a picture of John the Baptist dressed in animal pelts while having sex; or the baby that looked like a frog because his mother had been holding a frog in her hand (a cure for fever) while having sex; or the white princess who gave birth to a black baby because she looked at a picture of a “Moor.” These stories circulated well into the 19th century, and maternal imagination continued to be invoked as a cause of congenital anomalies and disabilities until well into the 20th century.

So strong was the belief in the power of maternal imagination that doctors advised husbands to treat pregnant wives gently, to avoid upsetting them and to indulge their cravings for strange foods. But even these positive practices suggest a lurking fear of the harm that the mother’s imagination could do without proper disciplining. Women, naturally irrational, unstable and emotional, made poor caretakers of fetuses.

While “maternal imagination” is no longer a medical category, the basic idea that mothers pose a threat to their fetuses has continued to permeate our culture. Maternal imagination has been replaced in the late 20th and early 21st centuries with concerns about the effects of “stress” on pregnancy, which indicates lingering concerns that a woman’s mental state can harm her fetus. A search in the PubMed database for “stress” and “pregnancy” pulled up over 20,000 articles on the impact of maternal stress on the developing fetus.

By contrast, a search for “environmental toxins” and “pregnancy” pulled up just 651 articles. This striking disparity indicates the degree to which concerns about fetal well-being still focus on threats to the fetus from the mother, not the external environment.

Yet there is overwhelming evidence that exposure to chemicals and heavy metals in utero poses far greater risks to the life and health of fetuses than maternal emotions. Two examples illustrate this point. In Flint, Mich., where residents were exposed to high levels of lead in their drinking water, a study of fetal death found a 58 percent increase in miscarriages in the aftermath of the lead exposure. The researchers noted that this was almost certainly an undercount.

Likewise, Native American reservations in the western United States have suffered severe heavy metal contamination from abandoned mines for years. Infant mortality rates among Native Americans are 28 percent higher than in non-Hispanic whites, and rates of birth defects are 50 percent higher. These rates are not all attributable to heavy metal contamination, but lack of safe drinking water and soil contamination are linked to a wide range of health problems on reservations.

And yet, instead of legislatures focusing on environmental hazards like these that pose such risks to fetuses, elected representatives seek to protect them from their mothers. Georgia’s HB 481 explicitly states that “the homicide of a child” includes the killing of embryos or fetuses with “a detectable human heartbeat.” This would make any abortion after six weeks a homicide. But it would also transform miscarriages into suspicious deaths, and subject women who miscarry to intrusive investigations. If the state finds a woman to be responsible for her miscarriage, because she used certain drugs, or engaged in strenuous physical activity, or any other reason, she could be prosecuted for second-degree murder.

This law, and others like it, reflects a culture that treats pregnant mothers suspiciously, and fails to understand the risks of pregnancy. After thousands of years, it’s time to end such suspicion once and for all, and instead understand what the science teaches us: The last thing we ought to be doing is criminalizing a tragedy that happens all too often despite the best efforts of expectant mothers.