7 Serious Effects Of Passive Smoking During Pregnancy

effects of passive smoking during pregnancy

As per the American Pregnancy Association, in the United States, a staggering 12–20% of pregnant women smoke, leading to birth defects in the baby, preterm delivery, and even fetal death.1 As a mom-to-be, you have taken the wise decision to quit smoking, if not for eternity then at least till your baby is born and eventually weaned off your breast milk. But probably you still like to breathe in a whiff when someone else is smoking nearby. How harmful can a puff of secondhand smoke be?

Sadly, the effects of passive smoking during pregnancy are quite harmful. Secondhand smoke (SHS) is known to cause 6 million premature deaths per year, and babies are part of this list. The tobacco smoke you inhale comes out of the lit end of the cigarette (or any smoking product). So there’s no filter to protect you from the 4,000 chemicals present in it, many of which may cause cancer. Your baby breathes in what you breathe in, and all these chemicals find their way to your baby too via your bloodstream. Nicotine, carbon monoxide, and other chemicals can cross your placenta and affect your baby.2 The effects of passive smoking during pregnancy include miscarriage, premature birth, low birth weight, birth defects, sudden infant death syndrome, poor psychological development in the child, and increased risk of addiction. Here’s a detailed look at the 7 effects of passive smoking during pregnancy.


1. Miscarriage

Pregnant women are most likely to be exposed to secondhand smoke at home, and previous studies have found that the partner’s smoking habits could lead to miscarriages. A study conducted in Hong Kong found that women whose husbands smoked more than 20 cigarettes a day were twice as likely to have a miscarriage than those who had non-smoker husbands.3

2. Premature Birth

A study on 209 women, of whom 43 were exposed to secondhand smoke, found that there was a higher percentage of premature births in the SHS group than in the non-smoker group.4 Passive-smoking moms also have significantly higher risks than non-smokers of hypertension, anemia, and premature rupture of membrane (PROM) or water breaking prematurely.5


3. Low Birth Weight

Many studies show a clear association between passive smoking and low birth weight (LBW). A Malayasian study on 209 women exposed to secondhand smoke (SHS) during pregnancy and 211 women not exposed to any found that more babies in the SHS group had low birth weight.6 And for every extra cigarette the moms smoked passively, there was a reduction in the baby’s birth weight by 12.9 g. This is because cigarette smoke can restrict the growth of the baby in the uterus.7

While nicotine can reduce fetal blood circulation, carbon monoxide can reduce oxygen supply to the fetus.8


4. Birth Defects

Passive smoking can cause birth defects in babies. The toxins present in the smoke can cause limb reduction defects or shortened limbs, clubfoot, cleft lips and palate, eye defects, and gastrointestinal effects. Many studies clearly associate passive smoking and birth defects.9

5. Sudden Infant Death Syndrome (SIDS)

Passive smoking during pregnancy can be a contributing factor to the sudden, unexplained, and unexpected death of an infant before 1 year of age. This is known as the sudden infant death syndrome (SIDS). The risk is higher if the mom smokes after the baby’s birth. Nicotine and the other toxins in smoke can adversely affect the development of brain cells and the nerve network. They can also make the baby prone to respiratory infections, which increases the risk of SIDS.10 Passive smoking can also affect the immune system of the fetus, thus affecting its ability to survive infections.11


6. Compromised Psychological Development

It has been found that, passive smoking during pregnancy also affects the cognitive and psychological development of children. A study on 91 children aged 6–9 found that kids whose mothers were non-smokers performed better at tests on speech and language skills, intelligence, visual/spatial abilities, and behavior (rated by the mothers) than did kids whose mothers smoked actively or passively. The kids of the passive smokers, however, performed better than those of active smokers.12

7. Increased Risk Of Tobacco Abuse

Studies have found that smoking during pregnancy, both actively and passively, exposes babies early to nicotine, which is addictive, and makes it likely for them to take to tobacco abuse as adolescents.13


If you are pregnant and still haven’t quit smoking, please do so now. Here’s what you need to do to quit. If your partner is pregnant, stop smoking near her. Please remember, there is no such thing as a safe level of SHS exposure.14 Also make your home a smoke-free zone. Smoke residues can remain for a long time and cause harmful effects. This is called thirdhand smoking. A healthy baby is the responsibility of both parents.