Late in my pregnancy with my daughter, Layla, I had a glass of red wine every once in a while. And while I took prenatal vitamins, I'm sure I missed a day somewhere in there. I definitely – absolutely, without-a-doubt – ate more junk food than is recommended by most health organizations. Does that mean I should go to jail? It may sound ridiculous, but that's the very real slippery slope we're on, thanks to laws criminalizing pregnant women – and treating their personhood as secondary to their pregnancy.

Earlier this month in Tennessee, 26-year-old new mother Mallory Loyola became the first person arrested under a new law that makes using narcotics while pregnant a criminal offense. Loyola is facing charges of assault against her fetus – she was arrested two days following birth, after she allegedly tested positive for amphetamines.

While Tennessee is the only US state with an explicit law criminalizing drug use by pregnant women, Lynn Paltrow, the executive director of the National Advocates for Pregnant Women, says that multiple states arrest pregnant women anyway, simply by classifying fetuses as children.

Alabama, for example, has arrested over 100 pregnant women since 2006 under a law meant to stop people from bringing children to place where drugs are made, like meth labs. And earlier this year, that state's supreme court ruled that women can be charged with "chemical endangerment" of a child if they use a controlled substance while pregnant. The definition of pregnancy is so broad, Paltrow says, that a woman could smoke some pot with her boyfriend one night, have sex, get pregnant and, under Alabama law, face 10 years in jail for that one use of marijuana.

Obviously, doing drugs while pregnant is a horrible idea. But criminalizing addicted pregnant women who need treatment is bad for babies and their mothers. It's a short-term, punitive measure with no positive lasting impact to simply ensure that pregnant women who need drug treatment and pre-natal care won't seek either of those options, for fear of having their children taken away from them.

It also raises questions of just how a state will go about finding pregnant women to prosecute: I'm betting the local prosecutor's office won't be doing random drug-testing in hospitals populated largely by affluent white patients.

And Paltrow says that targeting drug-using women is just the start. "This is about making pregnant women – from the time an egg is fertilized – subject to state surveillance, control and extreme punishment."

But beyond the problems of these current laws, criminalizing women's actions during pregnancy is a dangerous road to go down. How long will before drinking while pregnant is illegal? Will we arrest someone like me who had an occasional glass of wine? What if a woman decides not to take prenatal vitamins? Or has a C-section against her doctor's advice? (That one is less hypothetical: a woman in Utah was charged with murder because she delivered a stillborn baby after her doctor advised against a vaginal birth.)

Even worse, what happens when we decide that policing already-pregnant women isn't enough?

As I reported in my book, Why Have Kids?, the government has long been on a mission to reduce women to vessels for pregnancy. In 2006, the Centers for Disease Control and Prevention released guidelines instructing all women of childbearing age – whether they were pregnant or not, whether they even had plans to become pregnant or not – to care for their "pre-conception" health. Starting as soon as girls got their first period until they hit menopause, the CDC said that women should take folic acids, not smoke or "misuse" alcohol, refrain from drug use, avoid "high risk sexual behavior" and maintain a healthy weight. (There go my twenties!) What could eventually happen if a woman were to not follow these guidelines and have a miscarriage or stillbirth? Could she be sent to jail, too?

A world in which all women who can get pregnant are considered "pre-pregnant" – and in which the state has more of a vested interest in protecting any embryo or fetus at any stage of development than the woman herself – is the stuff of nightmares, and a frightening future that's already upon us.

But a pregnant woman is still a person under the law, with the right to make decisions – even poor ones – about her own body. Instead of living in some Margaret Atwood-style dystopian world where we regulate, monitor and punish vulnerable pregnant women, let's instead make sure that those who need help, get it – and not from inside a jail cell.