Secondhand smoke exposure during pregnancy carries substantial health risks for both the pregnant individual and the developing fetus. These risks extend from complications during pregnancy to lasting health issues in the child after birth, underscoring the need for avoidance.
What Secondhand Smoke Is
Secondhand smoke, also known as environmental tobacco smoke or passive smoke, is a combination of two forms of smoke from burning tobacco products. One component is mainstream smoke, which is exhaled by a person who smokes. The other component is sidestream smoke, emitted directly from the burning tip of a cigarette, cigar, or pipe. Sidestream smoke is particularly hazardous because it contains higher concentrations of many toxic chemicals compared to mainstream smoke.
Secondhand smoke contains over 7,000 chemicals, with at least 250 known to be harmful and around 70 identified as carcinogens. These include substances such as formaldehyde, benzene, carbon monoxide, nicotine, and ammonia.
How It Harms Pregnancy
Toxic chemicals from the smoke enter the pregnant person’s bloodstream and can readily cross the placenta, directly affecting fetal development. Nicotine, for instance, can reach fetal concentrations 15% higher than in the mother and affects placental function, reducing blood flow to the developing baby. Carbon monoxide also restricts oxygen supply, which can slow fetal growth.
One significant risk is an increased chance of ectopic pregnancy, where the fertilized egg implants outside the uterus. Secondhand smoke exposure also raises the risk of miscarriage, with studies indicating an 11% increased risk. For stillbirth, the risk can be 23% higher due to secondhand smoke exposure.
Premature birth, defined as delivery before 37 weeks of pregnancy, is another concern, with exposure significantly increasing this likelihood. Babies born prematurely often face underdeveloped lungs and other health complications. Furthermore, secondhand smoke exposure is linked to low birth weight, with exposed babies often weighing less than those not exposed. This can result from restricted fetal growth, as the harmful chemicals can damage the baby’s DNA and interfere with nutrient and oxygen delivery.
Placental abruption, where the placenta detaches from the uterine wall prematurely, is also associated with secondhand smoke exposure. Research indicates that secondhand smoke can increase the risk of placental abruption by about 2.3 times, potentially leading to severe bleeding and reduced oxygen supply to the fetus.
Lasting Impacts on Child Health
One of the most serious post-birth risks is Sudden Infant Death Syndrome (SIDS). Babies exposed to secondhand smoke during pregnancy have a higher chance of SIDS, partly because the chemicals can affect brain development and interfere with breathing regulation.
Children exposed to secondhand smoke prenatally are also more susceptible to a range of respiratory problems. They have an increased risk of developing asthma, bronchitis, and pneumonia. These children often experience more frequent ear infections and generally have lower lung function compared to those not exposed. The damage to developing lungs can lead to long-term respiratory challenges.
Beyond respiratory and sudden infant death risks, prenatal secondhand smoke exposure has been linked to potential developmental and behavioral issues in childhood. Studies suggest connections to learning difficulties and attention deficit hyperactivity disorder (ADHD). The harmful chemicals can impact the brain development of newborns, affecting physiological, sensory, motor, and attention responses.
Steps to Avoid Exposure
Creating smoke-free environments at home and in vehicles is a primary step. This means ensuring no one smokes indoors or in enclosed spaces where a pregnant person might be present. Even if a smoker goes outside, residue from smoke can remain on clothing and skin, which can still transfer toxins.
It is also beneficial to politely ask others not to smoke in your presence. Communicating the risks of secondhand smoke to family and friends can help them understand the importance of avoiding smoking around pregnant individuals. Avoiding public places where smoking is permitted can further reduce exposure.
Remember that there is no safe level of exposure to secondhand smoke; even brief encounters can be harmful. Proactive measures to eliminate smoke from both public and private spaces are beneficial for maternal and fetal health.