All women are recommended to stop smoking during pregnancy. Is this enough? No, research has shown that quitting smoking is not enough to eliminate the risks associated with exposure to cigarette smoke. In fact, many women are exposed to the passive smoke of friends and family (called second-hand passive smoke) or to the residues left by smoke on fabrics and also on furniture, in the car or in other closed places (called passive third-hand smoke).
What is secondhand smoke?
Passive smoking is by definition the involuntary inhalation by people who do not smoke, of substances coming from cigarettes, pipes or cigars of other individuals. Passive smoke can be inhaled if we live with a smoker or if we frequent clubs or environments where we smokes.
There are approximately 4,000 chemicals found in secondhand smoke, many of which are classified as carcinogens.
What are the consequences of passive smoking in pregnancy?
Scientists from the University of Pittsburgh, Graduate School of Public Health conducted a study that led them to claim, in the study published in The Open Pediatric Medicie Journal that a pregnant woman breathing secondhand smoke exposes her unborn child to the risk of permanent damage to her health. According to this study, the consequences between active and passive smoking are comparable, infants from smoking mothers and those born to non-smoking mothers but subject to passive smoking, had the same genetic abnormalities.
These anomalies result in greater susceptibility to certain diseases such as cancer as well as the lowest birth weight.
The study confirmed previous scientific work in which abnormalities in the HPRT gene were found in the umbilical cord blood of infants of non-smoking mothers exposed to passive smoking during pregnancy. In addition to these, however, they have been found other dangerous genetic mutations such as those induced on the gene for glycophorin A (GPA) which is a representative of oncogenic genes (oncogenic genes are genes that determine the transformation of a cell into a cancerous one).
Other consequences of secondhand smoke in pregnancy are:
Pregnant women can be exposed to this type of smoke without even realizing it. In fact, it exists a more subtle exposure, which is represented by the residue left by cigarette smoke on furniture, carpets, paint, etc. These residues can hang around for months or years.
Harmful substances can enter the bloodstream when you touch something that contains the residue or breathe in the residue. Once in circulation these substances are shared with the child. A study conducted at the Los Angeles Research Institute found that so-called “third-hand” smoke residues have a detrimental effect on prenatal lung development. These effects can cause breathing problems later in their life.
What effects does passive smoking have on the baby born?
It is necessary for the baby to have limited exposure to secondhand smoke even after birth. Children who come into contact with secondhand smoke are more likely to experience SIDS. Additionally, children exposed to secondhand smoke experience adverse effects on their immune systems.
They are more likely to have ear infections, colds, respiratory ailments, and dental problems. Third hand smoking is likely to be as harmful as second hand smoking, so it’s important keep your child away from areas that contain smoke residues.
What is the relationship between passive smoking in pregnancy and breastfeeding?
In 2019, the first systematic review was published to assess the association between passive smoking in pregnancy and breastfeeding. Maternal exposure to cigarette smoke during pregnancy was associated with an increased frequency of discontinuation of breastfeeding before the infant was six months old.
Furthermore, exposure to secondhand smoke during pregnancy was associated with shorter duration and prevalence of breastfeeding.
Smoking or parenteral nicotine are already known to be associated with low concentrations of prolactin. Prolactin is important for metabolic homeostasis and is associated with the lactating mammary gland, increasing milk proteins, lactose and lipids. It is important to note that an animal study reported that nicotine was one of the risk factors for inhibition of prolactin release.
Furthermore, the duration of breastfeeding among women exposed to secondhand smoke tends to be lower than the WHO recommendation. WHO / UNICEF recommends exclusive breastfeeding for up to six months, which should then continue for up to two years or more supplemented with solid foods.
Given the many benefits of breastfeeding on the baby (but also on the woman) it is essential to insist on an adequate prevention campaign against smoking.
If you are looking for a pregnancy, if you are already pregnant or have recently had a child, it is important to minimize the presence of direct or passive smoking, second or third hand. Do not smoke if you are trying to become pregnant, this also applies to your partner, and do not smoke during pregnancy.
If your partner smokes, make sure they do it outdoors and don’t walk into the house wearing the clothes they smoked in. For example, you can advise him to wear a coat or sweatshirt when he smokes and to remove it before entering the house.
Also, after being exposed to cigarette smoke, it is important that you wash your hands before touching the baby.
Grant, SG Qualitatively and quantitatively similar effects of active and passive maternal tobacco smoke exposure on in utero mutagenesis at the HPRT locus. BMC Pediatr 5, 20 (2005). https://doi.org/10.1186/1471-2431-5-20
Suzuki, D., Wariki, WMV, Suto, M. et al. Secondhand Smoke Exposure During Pregnancy and Mothers’ Subsequent Breastfeeding Outcomes: A Systematic Review and Meta-Analysis. Ski Rep 9, 8535 (2019). https://doi.org/10.1038/s41598-019-44786-z
Mojibyan M, Karimi M, Bidaki R, Rafiee P, Zare A. Exposure to Second-hand Smoke During Pregnancy and Preterm Delivery. Int J High Risk Behav Addict. 2013; 1 (4): 149-153. doi: 10.5812 / ijhrba.7630
Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center (LA BioMed). “‘Thirdhand smoke’ poses danger to unborn babies’ lungs, study finds.” ScienceDaily. ScienceDaily, April 19, 2011.