The effects of smoking during your pregnancy

Smoking is a significant contributor to the burden of illness and disease in Australia, despite being the single most preventable cause of ill-health and death. Around 30% or 3 in 10 women smoke throughout their pregnancy, which can have serious implications on health and pregnancy outcomes.

Why is smoking dangerous during my pregnancy?

Every inhalation of a cigarette exposes both you and your baby to over 4000 potent chemicals. Even if you don’t smoke but your partner or another household member does, then this is passive smoking and still carries dangerous exposure to toxins. Often we are unaware of the serious impact cigarettes has on our health, especially in pregnancy, and this week addresses this important topic.

The most dangerous ingredients found in a cigarette include nicotine, tar and carbon monoxide that will reach your baby with every inhalation.

  •  Nicotine is responsible for the stimulant properties or ‘rush’ you feel when inhaling a cigarette. This toxin causes the body to release substances that increase your heart rate, raise your blood pressure and vasoconstrict or squeeze your vessels. This then leads to reduction in blood flowing to your uterus and through the umbilical cord to the fetus.
  • Carbon monoxide decreases the amount of oxygen carried in your blood, which reduces the amount that travels to your baby via the umbilical cord3,5. Consequently your baby will become stressed and beat their heart much more rapidly in efforts to obtain enough oxygen.
  • Tar contains bad substances that stick to the walls of our arteries, reducing the amount of blood that can flow through them, and can cause them to clog or form clots.
  • Other chemicals can have negative impact on the development of your baby and creates a very unhealthy environment for which it grows in.

How will smoking affect my pregnancy?

Smoking has a profound impact on pregnancy, including complications during the antenatal and intrapartum period, fetal health and wellbeing, as well as your long-term health outcomes.

Pregnancy complications include:

  • Reduces fertility – Smoking can delay conception, or achieving pregnancy, by average of 2 months as well as increase the risk of IVF failure.
  • Placental abruption – This is a serious condition that occurs when the placenta detaches from the lining of the uterus lining, which may lead to severe pain and bleeding, shock, and potential for emergency delivery due to risk of death to both you and your baby. If you smoke more than 20 cigarettes a day, you are at double the risk of this occurring.
  • Miscarriage and stillborn – Smoking contributes to up 10% of total miscarriages, and also increases chances of having a stillborn baby.
  • Preterm premature rupture of membranes and preterm birth – Smoking increases the chances of you going into labour earlier than expected, with either contractions or waters breaking. This can mean your baby is underdeveloped at the time of birth, especially their lungs, and may require ventilator assistance or a longer stay in hospital in an intensive ward.

Smoking impacts on your baby’s health through:

  • Fetal movements – One cigarette will decrease your babys movements in your womb for at least an hour, due to the deprived blood supply which carries oxygen and nutrients in which the baby needs to move.
  • Fetal growth restriction and low birth weight babies  – Up to 30% of smoking mothers will deliver smaller than average sized babies. Fetal growth restriction refers to when your baby grows at a rate slower than what is expected during your pregnancy. This is worrisome, as your baby will be at increased risk of suffering from poorer health prior to being born, will require close monitoring and increases your risk of having an emergency caesarean section at a time earlier than expected if your babys health deteriorates quickly. Once born low birth weight babies tend to suffer from more childhood illnesses and may continue to grow at a slower rate than other children.
  • Fetal anomalies – Smoking can interfere with the development of your baby and cause cardiovascular defects, problems with musculoskeletal development, cleft lip and palate, and poor gastrointestinal organ formation.
  • Increased risk of Sudden Infant Death Syndrome (SIDS) – Smoking either during pregnancy or postpartum period is a major risk factor for this condition. It increases risk up to three times that of a non-smoker baby with risk increasing proportionally to the number of cigarettes smoked.
  • Increased risk of childhood illnesses – Exposure as an infant can affect your child’s health for years to come, increasing chance they will suffer from colds, asthma and other lung illnesses, learning disabilities, physical growth problems, and risk of overweight or obesity.

Smoking affects your health by:

  • Breastfeeding – Smoking can reduce your capacity to produce breastmilk which can deprive your baby of essential nutrients. Some of the potent cigarette chemicals also will pass into your breastmilk and be delivered to your baby during feeding, causing further harm.
  • Increased risk of disease – Smoking will increase your chances of developing cardiovascular disease, clots in legs known as deep vein thrombosis, maternal respiratory disease, lung cancer, osteoporosis, and cervical disease and cancer

Smoking also has negative effect on our diet. Smokers have been found to consume less fruits and vegetables, and eat foods with a higher fat content, as well as more alcohol and caffeine. This may be because smoking isn’t paired well with healthy ‘raw’ foods but rather, the processed types. They are also less likely to be engaged in regular physical activity.

What are the recommendations?

Smoking is NOT recommended during pregnancy and you are strongly advised to quit prior to conception.

Sadly of those women that do manage to quit, over half of these will take up the habit again within 6months of baby being born. This increases to 70% by 12 months.

Recommendations are:

  1. There is NO SAFE LEVEL for smoking during pregnancy and you are strongly advised to quit.
  2. It is never too late to quit and quitting at ANY TIME during pregnancy is likely to result in less harmful effects of smoking on your baby.
  3. If you can’t quit then you must at least cut down to half your current smoking amount. This will not eliminate the damage to your growing baby, however will reduce impact of cigarettes on your own health.
  4. Adopt the 4 D’s to help quit – Delay, Deep breathe, Drink water, Do something else.
  5. Be honest and tell your doctor that you are a smoker to allow them to help you achieve your quitting goal. Interventions during pregnancy have shown to be successful and double the quitting rates.
  6. If someone at home smokes make a rule for no smoking in the house or in a confined space with you. Try to also avoid environments with smoke such as some restaurants, private parties or other community places.
  7. If you are unable to quit via behaviour, Nicotine Replacement Therapy (NRT) can be used during pregnancy. Although there are limited studies as to its use during pregnancy NRT exposes your baby to less harmful substances versus a cigarette, and benefits outweight harmful effects of smoking. You must speak with your doctor prior to commencement of NRT.

The message should be clear: every cigarette exposes both you and your baby to a cocktail of potent chemicals and will also deprive your baby of oxygen and blood. Smoking during pregnancy must be discouraged amongst you, your friends and family. Adopt the 4Ds and “Do something else” – cook amazing meals, drink lots of water and fresh juices, and enjoy others company without the horrible smoke.


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