Light smoking can impact the health of both you and your baby during pregnancy and beyond. While quitting may seem challenging, it could help prevent low birth weight and premature birth.

Some believe it’s OK to smoke while pregnant if it’s just a little, but this isn’t really accurate.

In fact, the Centers for Disease Control and Prevention (CDC), World Health Organization (WHO), and American Academy of Pediatrics (AAP) agree no amount of smoking during pregnancy is safe and recommend quitting as the most beneficial course of action.

They also highlight the effects of firsthand and secondhand smoke, including:

Read on to learn more about how smoking may impact your pregnancy, the safety concerns of light smoking, why quitting is important, and how to get started.

How much is “light” smoking?

Most researchers define light smoking as using fewer than 10 cigarettes per day.

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Smoking harms the developing fetus throughout pregnancy, but smoking at different stages may impact fetal development and your health in different ways.

First trimester

Smoking in the first trimester is connected to a higher risk of some congenital birth defects including gastroschisis.

Second trimester

Light smoking, even just one to two daily cigarettes during the first and second trimesters, is linked to a higher risk of preterm birth per 2020 research.

A 2019 study suggests that the longer smoking continues into pregnancy, the higher the chances of preterm birth.

Third trimester

Third-trimester smoking may especially restrict fetal growth and contribute to lower birth weights in early, full, and late-term births.

Smoking in the third trimester could also increase an infant’s chances of experiencing atopic dermatitis and eczema, according to 2017 research.

Which trimester is smoking most harmful?

Smoking during the first trimester of pregnancy can be especially harmful in terms of birth defects because the first trimester is when most of the fetal anatomy forms.

Still, smoking into the second and third trimesters is also more strongly linked to restricted fetal growth, which can come with developmental concerns impacting heart, lung, and brain function.

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Moderate and heavy smoking tend to magnify the pre-existing risks that accompany light smoking, including:

  • Ectopic pregnancy: Smoking even 1–4 cigarettes was connected to higher chances of ectopic pregnancy in 2019 research.
  • Birth defects: Smoking 1–5 cigarettes daily is connected to higher chances of an infant with cleft lip and palate.
  • Restricted growth and low birth weight: Light smoking could restrict fetal growth and contribute to a lower birth weight for gestational age.
  • Preterm birth: Even just 1–2 cigarettes per day in the first or second trimester could increase the chances of preterm birth.

Exposure to secondhand smoke, even if you don’t smoke yourself, is also linked to preterm birth.

While it’s technically possible to smoke during pregnancy and experience no adverse outcome, that doesn’t mean it’s safe — the risk of harm remains.

There’s no way to guarantee that any amount of smoking or cigarettes won’t cause health problems for you or your developing baby.

Smoking makes it harder for the developing fetus to get enough oxygen to grow, so it’s less stressful on the baby to quit smoking altogether than to continue smoking in small amounts, regardless of how much you currently smoke.

Compared to continuing to smoke through the whole pregnancy, quitting during the first and second trimesters may boost your baby’s chances of being born full-term at a weight typical for their age.

It might feel challenging, but many support options can help you stay on track. If you’re not sure where to start, consider:

  • Quitting as a household: A smoke-free household is one of the best predictors for continuing to keep from smoking during pregnancy and beyond. A 2017 study highlights that for anyone who’s trying to quit, recurrence is less likely if your friends and family also don’t smoke.
  • Practicing self-compassion: It’s common to have a recurrence of smoking when you’re trying to quit, but this doesn’t mean quitting is impossible. Fostering self-compassion could help you stay in a mindset that supports cessation even after a recurrence.
  • Managing stress: Relaxation techniques like meditation are unlikely to single-handedly help you quit smoking, but they can feed into that outcome, especially if stress is what causes you to reach for a cigarette in the first place. As a bonus, stress management also supports a healthy pregnancy.
  • Connecting with mental health support: Forms of therapy like motivational interviewing could help people quit smoking as well as develop emotional regulation skills and self-efficacy.
  • Considering NRT and smoking cessation medications: Nicotine replacement therapy (NRT) and medications for smoking cessation could also be an option if you’re having trouble quitting without their support. It’s best to check with your doctor about which option, if any, is safest for you during pregnancy.

Learn more about how to quit smoking while pregnant.

Even one daily cigarette can increase the risk of pregnancy complications and adverse outcomes for the developing fetus. Smoking brings different risks depending on your current stage of pregnancy, but quitting at any point will help your baby get more oxygen and improve their chances of a healthy outcome.

While quitting is worthwhile, it can feel difficult. Smoking when you didn’t mean to sometimes happens, and it doesn’t mean you’ll never be able to quit. Remember, each smoke-free day can give your baby a better chance at health.