Experts from Department of Obstetrics and Gynecology readily agree that smoking cigarettes by the mother during pregnancy is probably the No. 1 cause of adverse outcomes for babies.

Smoking when pregnant is strictly unacceptable because the effects of this can be disastrous for the baby. It has serious complications on almost all systems of the body of the pregnant woman and the developing baby.

Smoking also puts the mother-to-be at risk for complications such as vaginal bleeding, premature rupture of the membranes, and premature delivery.

The effects on the baby can be short-term in which case the baby dies in the womb before it is born. Long-term effects cause more suffering in which the baby is born too soon or it may be born too small, or it may develop congenital defects.

The reason for this is that cigarette smoke has more than 4000 chemicals each of which is toxic, mutagenic and carcinogenic. Tar, nicotine, and carbon monoxide gas are the three most toxic of them.

Of these three, nicotine and carbon monoxide, which can travel through the blood, account for almost every smoking-related complication in pregnancy. Both together are responsible for the reduction of your baby’s supply of oxygen.

Nicotine narrows the blood vessels of the body including the ones in the umbilical cord and chokes off oxygen to the baby in the uterus. It is akin to breathing in through a choked narrow straw.

The red blood cells that carry oxygen pick up carbon monoxide absorbed from the cigarette smoke in the blood instead of oxygen. The mother and the baby thus have more of the toxic gas instead of oxygen in their blood.

Shortage of oxygen, which is so vital for the baby’s growth, can have a devastating effect on the developing baby’s physical and mental development.

The unsolvable problem is that the medical fraternity is helpless and can do nothing about it when the pregnant mother cannot control her addiction and continues to smoke throughout her pregnancy.

An existing comorbidity during pregnancy like diabetes or hypertension can be treated but it is the mother-to-be only who must enforce willpower and stop smoking on her own. There are effective aids that will help her to stop smoking.

Why is smoking during pregnancy dangerous?

Smoking when pregnant causes ill effects on the developing fetus and can produce harmful effects on its development.

You not only harm yourself but also take a very high risk of harming your baby, which is developing in your womb. And as explained in the causes of smoking, addiction to tobacco smoking is very strong, which makes it difficult to stop smoking. The withdrawal symptoms that follow when you try to stop can be quite problematic.

A smoking pregnant mother is in a rather difficult situation as she has to handle addiction on one hand and on the other hand, is her maternal instinct and care for her baby, which is developing in her womb.

The baby is developing in its mother’s womb with the help of nutrition it gets through the blood of the mother. The mother’s blood is the only source of nutrition and oxygen of the developing fetus.

This transfer of nutrition and oxygen from the mother’s blood to the blood of the fetus takes place through the placenta. The placenta is the connecting cord between the mother and the fetus in the uterus.

When you smoke during pregnancy, the toxic contents of the cigarette smoke get transferred from the mother’s blood to the blood of the fetus.

Instead of nutrition, the fetus gets fed with toxins, which are going to hamper and retard its development and produce congenital defects.

As explained in the post on the contents of cigarette smoke, carbon monoxide, which is a toxic gas in the cigarette smoke, takes the place of oxygen and binds itself together with the hemoglobin in the blood.

It is this carbon monoxide instead of oxygen that gets carried to all the parts and organs of the mother’s body causing enormous harm.

Carbon monoxide also crosses the placental barrier and travels through the blood to the fetus making it vulnerable to complications.

However, do note that there is no safe level of smoking in pregnancy and the more cigarettes you smoke; the greater are the chances of your baby developing these health problems. Even that one cigarette has the potential to do damage.

Effects of smoking on the unborn baby

When the mother resorts to and continues smoking during her pregnancy months, more than her, the developing baby inside her womb is exposed to great risks.

Effects on life of newborn

Studies indicate that pregnant women who smoked less than 10 cigarettes a day are 21% more likely to give birth to a stillborn while pregnant women who smoked more than 10 cigarettes per day bore a risk of 26% of giving birth to a dead baby or babies who die within 4 weeks of birth (neonatal death).

Incidences of miscarriages are also more. This could be due to placental abruption (detachment of placenta).

Effects of smokng on size of baby

If the mother has smoked when pregnant, she is very likely to have a premature delivery. The newborn is likely to be underweight and smaller in size than normal. The body of such a baby who has been exposed cigarette smoke during the prenatal stage is underdeveloped.

A pack a day could reduce the weight of the newborn by about half a pound, while two packs could reduce the newborn’s weight by two pounds.

Though this does not look very abnormal, do remember that this has happened due to the underdevelopment of the fetus in the womb because of smoking, and will have further long-term adverse effects during its lifetime.

Smoking can cause heart defects in the baby

A study conducted by the Centers for Disease Control and Prevention (CDC) in the United States in February of 2011 concluded that smoking while pregnant increases the risks of the baby developing congenital heart defects by anywhere between 20% to 70%. The heart rate is also increased. These congenital heart defects include:

  • Congenital pulmonary stenosis causing right ventricular outflow obstruction leading to reduced blood flow from the heart to the lungs.
  • An atrial septal defect can develop. It is a defect in the septum dividing the two upper chambers of the heart. This “hole” in the heart can lead to oxygenated blood in the left atrium to mix with poor oxygen blood in the right atrium.

These heart defects make the newborn potential candidate for heart diseases such as congestive cardiac failure and pulmonary hypertension later in life.

Affects on the lungs of the newborn

Having been exposed to cigarette smoke contents in the womb, the newborn may not be able to breathe on its own after delivery. The newborn may have to be put on a respirator for a few days or even a few weeks.

This is because the lungs have not developed as they should and because of these underdeveloped lungs, the baby becomes vulnerable to developing asthma. Smoking paralyzes the cilia, which line the airways, and therefore, such babies are very prone to respiratory tract problems.

SIDS – Sudden infant death syndrome

Babies of smoking mothers may even die within one year due to SIDS (sudden infant death syndrome). This is the leading cause of death in infants in the United States where the cause of death remains unknown. Risk of SIDS increases 2 to 5 times when the woman resorts to smoking while pregnant.

Effects on the brain of fetus

The brain of the newborn of a smoking mother shows lifelong effects. During development in the womb, the brain of the fetus has been exposed to carbon monoxide and nicotine and is, therefore, retarded. Though there is normal intelligence, there is difficulty in speech, reading, and learning.

The child shows behavioral problems and a relatively low IQ. This low IQ in spite of normal intelligence is because such children are unable to translate their intelligence into everyday affairs.

Frequent illnesses

Babies born to a smoking mother fall ill more frequently during their first year and have to be hospitalized more often.

Effects smoking on lactation

Smoking does affect lactation adversely by interfering with the milk producing hormones. Therefore, smoking mothers either do not breastfeed their baby or wean early. This increases the baby’s risk to SIDS.

Effect of second-hand (passive) smoke on the fetus

Passive smoking is inhaling second-hand smoke. This is smoke that is exhaled by the smoker near you. If you are pregnant (and even otherwise) and find a smoker near you, do stay clear. The dangers of second hand smoke are equally serious.

Keep a safe distance so that you do not inhale a smoker’s exhaled smoke. Exposure to second-hand smoke during pregnancy increases the chances of you and your newborn developing asthma, emphysema, bronchitis, lung cancer, heart disease, allergy.

Risk of malignancy

There is sufficient evidence to show that smoking during pregnancy increases the risk of childhood leukemia and hepatoblastoma in the offspring. Hepatoblastoma is a malignant liver tumor. Smoking is the highest risk factor that predisposes you to cancer. 

Smoking habit

Children of smoking mothers are very likely to become smokers early on in life.

What should you do to stop smoking?

If you are a smoker and find yourself pregnant, there is only one thing you can do and that is to stop smoking. Take professional help if necessary. Ideally, smoking should be stopped when you plan to have a baby; that is before you conceive. But it is never too late. Do whatever you can to quit. The benefits of giving up smoking are tremendous.