IQOS While Pregnant: What the Evidence Actually Says
Nicotine crosses the placenta whatever device delivers it. What heated tobacco removes, what it does not, and how to raise it with your midwife.
Quick answer
No tobacco product is considered safe in pregnancy, and heated tobacco is a tobacco product. Nicotine crosses the placenta regardless of the device and reduces blood flow to it. Heated tobacco does produce far less carbon monoxide than cigarettes, which matters, but it is not an established safe option. Speak to your midwife or doctor early.
Nicotine crosses the placenta whatever is delivering it. That single fact answers most of this question, and it does not change because the tobacco is heated rather than burned.
The rest is worth understanding properly, because “heated tobacco is not safe in pregnancy” and “heated tobacco is identical to smoking” are both slogans, and the truth sits between them in a way that actually matters for the decisions in front of you.
What nicotine does during pregnancy
Nicotine passes readily into fetal circulation and has been measured at levels similar to or higher than the mother’s. It is not a substance the placenta filters out.
It is also a vasoconstrictor: it narrows blood vessels, including the ones supplying the placenta. Reduced placental blood flow means less oxygen and fewer nutrients reaching the baby, and that mechanism is one of the reasons tobacco use in pregnancy is associated with low birth weight and preterm birth.
There is a second concern that is specific to nicotine rather than smoke. Nicotine acts on receptors involved in brain development, and the US Surgeon General has concluded that nicotine exposure during pregnancy and adolescence is harmful to the developing brain. That conclusion does not depend on combustion being present.
What heated tobacco removes, and what it does not
This is where honesty helps more than either reassurance or alarm.
Carbon monoxide is one of the main ways cigarette smoking harms a pregnancy. CO binds to haemoglobin far more readily than oxygen does, so the mother’s blood carries less oxygen to deliver. Heated tobacco does not sustain combustion, so it produces far less carbon monoxide. That is a genuine difference, and it is the reason midwives use CO breath tests as one measure.
Everything else carries over or is unknown:
- Nicotine delivery is in the same broad range as a cigarette in published studies. Dependence, and the vasoconstriction, come with it.
- It is still tobacco. The World Health Organization treats heated tobacco products as tobacco products under the Framework Convention on Tobacco Control, and its position is that all tobacco use is harmful.
- There is no pregnancy outcome data. Heated tobacco reached the market around 2014. Nobody has followed enough pregnancies for long enough to say anything reliable about birth outcomes, and no regulator has authorised a reduced-risk claim. In 2020 the US FDA allowed a reduced-exposure claim for IQOS versus cigarettes and specifically refused a reduced-risk claim.
So: not the same as smoking, not established as safe, and not recommended by any health authority during pregnancy.
The conversation with your midwife
Have it early, and do not round the number down.
Midwives and obstetricians are not there to judge how many sticks a day you use. They are there to adjust care, and the number changes what they do: how they monitor growth, how they read a CO test, whether they refer you to a stop-smoking service, whether medically supervised nicotine replacement makes sense for you.
In many countries NRT is offered in pregnancy precisely because continuing to use tobacco is considered the greater risk. Whether it is right for you is a clinical decision, made with someone who knows your history, not something to settle from an article.
Three things worth saying out loud at that appointment:
- The exact number of sticks on a typical day, including the bad days.
- Whether you also smoke cigarettes sometimes, which is very common among heated tobacco users and changes the picture.
- What you have already tried, and what made it fall apart.
What about someone else using it around you
This comes up constantly and rarely gets asked out loud, usually because it involves a partner.
Heated tobacco produces no sidestream aerosol, since nothing smoulders between puffs, so a room does not fill the way it does with cigarettes. That is a genuine difference from secondhand smoke. It is not the same as nothing: researchers measuring indoor air where heated tobacco is used regularly have found nicotine and fine particles above background levels, and nicotine also deposits on surfaces and soft furnishings over time.
The practical version is unremarkable and worth agreeing on early. Keep it out of the home and the car, especially the rooms where a newborn will sleep. If a partner is using indoors, this is a fair thing to ask them to move outside, and it is far easier to ask now than after the baby arrives.
If stopping outright feels impossible right now
Then start with the part that is possible today, because the alternative to a perfect quit is not nothing.
Stopping at any point in pregnancy improves outcomes. Earlier helps more, and there is no week after which it stops being worth doing. Nicotine largely clears the body within about 72 hours of the last stick, and placental blood flow is not a permanently altered thing, it responds to the absence of vasoconstriction.
Most people who stopped for good had tried before, often several times. Pregnancy is a common moment for the attempt that finally holds, partly because the reason is standing right there, and partly because it comes with more support than any other point in life.
The two-minute action that helps immediately: count today’s sticks and change nothing else. No target, no cutting, just an accurate tally. Do it for three days and you will walk into your next appointment with a real number rather than an estimate, which is exactly what your midwife needs and exactly what a taper has to be built from.
Puff Counter can hold that count for you, one tap per stick, with each week’s ceiling set from your own average rather than a figure someone else picked.
You do not need to have handled this perfectly to start handling it well. Tell your midwife the real number this week, and let them help with the rest.
Frequently asked questions
Is IQOS safer than smoking during pregnancy?
It removes most carbon monoxide, which is one of the main ways smoking reduces a baby's oxygen supply, so it is not identical to smoking. It does not remove nicotine, which crosses the placenta and constricts blood vessels. No health authority recommends it in pregnancy, and there is no pregnancy outcome data to rely on.
Does nicotine cross the placenta?
Yes. Nicotine passes readily into fetal circulation and has been measured at concentrations similar to or higher than the mother's. It also narrows blood vessels, including those supplying the placenta, which reduces the flow of oxygen and nutrients. This happens whether the nicotine comes from a cigarette, a heated stick, a vape or a pouch.
I only found out I was pregnant recently and I have been using IQOS. What now?
Stopping at any point in pregnancy improves outcomes, and the sooner you stop the more benefit there is, but there is no cut-off after which it stops being worth doing. Tell your midwife or doctor without editing the number down. They deal with this constantly and can offer real support, including medically supervised options.
Is nicotine replacement therapy an option in pregnancy?
In many countries NRT is offered during pregnancy under medical supervision, on the basis that it is considerably less harmful than continuing to use tobacco. This is a decision to make with your midwife or doctor, who will weigh the dose, the form and your own history rather than applying a general rule.
