Smoking during pregnancy is a significant health concern, especially since 20% to 30% of pregnant women smoke. Fortunately, many women quit during pregnancy or at least reduce how much they smoke.

Smoking during pregnancy harms both the mother's and the unborn baby's health, and can even be fatal to the baby. Some of the complications that cigarette smoking can cause during pregnancy include:

  • decreased fetal growth
  • low birth weight
  • miscarriage
  • placental abruption (the separation of the placenta, which nourishes the growing baby, from the uterus wall)
  • premature birth
  • still birth
  • sudden infant death syndrome (more than 18% of all deaths from SIDS are due to maternal tobacco use)

Mothers who smoke while pregnant may experience reproduction-related effects, such as low estrogen levels (this can lead to early menopause) and infertility.

How does smoking affect unborn and newborn babies?

Mothers who smoke while pregnant are exposing their unborn baby to nicotine (a highly addictive substance), carbon monoxide, and thousands of other chemicals (including cancer-causing agents) that are found in tobacco. With each puff of a cigarette, these toxic chemicals travel through the mother's blood, cross through the placenta, and enter the baby's body. When an unborn baby is exposed to nicotine, their heart rate increases and they begin breathing at a faster rate.

Women who smoke while pregnant have a higher risk of miscarriage or serious birth complications. Complications to the baby that can occur include:

  • higher risk of death at or soon after birth
  • high risk of getting infections or having other health problems
  • slower growth of the fetus
  • smaller size at birth (on average, 150-200 grams less than babies born to non-smokers)

After a baby is born, mothers who smoke while breast-feeding can still expose their baby to harmful chemicals through breast milk. Mothers should not nurse their baby while smoking or immediately after.

The effects of second-hand smoke exposure during and after pregnancy can also cause long-term problems for a child. Later in life, children of mothers who smoke are more likely to have:
  • asthma
  • changes in behaviour
  • impaired learning
  • a nighttime cough
  • respiratory infections
  • slower growth

If you are pregnant and smoke, talk to your doctor about ways you can cut down or quit. You and your baby will be thankful you did.

Written and reviewed by the MediResource Clinical Team