Carbon monoxide

Carbon monoxide is a poisonous gas that you can’t see or smell. It’s given off when things containing carbon burn.

Carbon monoxide is harmful to anyone, but particularly if you are pregnant as it stops your red blood cells from carrying as much oxygen as they should. You need oxygen to stay healthy during your pregnancy but so does your baby. Oxygen is vital to the development of babies – if you smoke you will be depriving you and your baby of the important oxygen you need to stay healthy.

Danger to your baby

To make up for this lack of oxygen, your body produces more red blood cells – but this makes your blood thicker and stickier and more likely to block blood vessels. If this happens in the placenta it can cause vital parts of the placenta to die meaning less vital nutrients and oxygen can get through to your baby.

The combined effect of thicker blood, less oxygen and narrow blood vessels mean that your heart has to work harder than it should as a smoker. Because your baby shares your blood your baby’s heart has to beat harder too.

The good news is that when you stop smoking your carbon monoxide levels drop very quickly. In 24 hours your carbon monoxide levels go back to the level of a non-smoker. Your blood will thin and your body begins to repair itself. The sooner in your pregnancy you can stop smoking, the more likely it will be that the risks to you and your baby will return to that of a non-smoker.

Carbon monoxide monitor

When you come to a stop smoking session for the first time we will measure your carbon monoxide level by asking you to do a breath test. This involves you holding your breath for 10-15 seconds and then blowing into a carbon monoxide monitor. Most monitors use a simple traffic light system to show you how much carbon monoxide is in your body. Some smokers will get a red light in their first session. The level of carbon monoxide recorded will depend on how many cigarettes you smoke, how deeply you inhale and how long it has been since your last cigarette.

Just 24-48 hours after your last cigarette you will get a green non-smoker reading. Carbon monoxide is the first toxin to leave your body when you quit. This is why each time you come to a session we ask you to blow into the monitor so you can see for yourself that you are a non-smoker.

If you are later on in your pregnancy you may notice that you feel your baby move more often and more strongly – this is because your baby now has all the oxygen they need and therefore more energy.

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