The gestation period is a critical phase in which environmental exposure can affect the development of the unborn baby. Cigarette smoking during pregnancy exposes the fetus to more than 7,000 chemicals, including the neurotoxin nicotine and the respiratory toxin carbon monoxide. These chemicals can easily cross the placenta and damage the fetal nervous system and lungs by disrupting normal cell differentiation. This article aims to describe the effects of smoking on the baby.
Disturbance of fetal brain structure and function
Cigarette smoking by the mother and passive smoking during pregnancy can seriously harm the health of the fetus. There is significant development of fetal brain structure and function as neurons proliferate, migrate, and form sophisticated synaptic connections. Maternal smoking and passive smoking inhibit the developmental process in the following ways:
Nicotinic Receptor Dysfunction
Nicotine is a foreign substance that causes many of the same reactions as acetylcholine, a key neurotransmitter involved in early brain development. Exposure to nicotine during pregnancy can impair neuronal differentiation, the process by which progenitor cells develop into functional neurons. This disorder also affects other neurotransmitter systems involved in emotional regulation and cognitive function.
Brain Structure Modification and Volume Reduction
Several neuroimaging studies show that maternal smoking during pregnancy causes significant structural changes in the developing brain. These include:
- Brain volume reduction: People exposed to maternal smoking before birth tend to have reduced volume in the frontal lobes and cerebellum.
- Cortical atrophy: THE dangers of smoking during pregnancy they include lower brain gray and white matter volume, reduction in surface area, and rotation.
- Microstructure configuration: Maternal smoking can alter the integrity of the white matter of the fetal brain, reducing the development of neural connections.
Neurodevelopmental Disorders
Structural modifications in the developing brain lead to various neurodevelopmental disorders. A large Korean mother-baby cohort study which includes more than 860,000 mother-child pairs found that maternal smoking is a significant and modifiable risk factor for Attention Deficit/Hyperactivity Disorder (ADHD). Although correlations were also observed with Autism Spectrum Disorder (ASD) and intellectual disabilities, the evidence linking maternal smoking to ADHD was strongest.
Impairment of fetal lung development and respiratory function
Among all body systems, effect of smoking on fetal lung development it is the most damaging. The deadly compounds in cigarette smoke make newborns susceptible to chronic respiratory problems.
Changes in the structure of the lung
The effect of smoking on fetal lung development can be observed through the effects of nicotine and carbon monoxide on both the physical development and biochemical composition of the lungs. Key changes include:
- Incomplete alveoli: Babies born to mothers who smoke often have fewer and larger alveoli, reducing the total surface area available for gas exchange.
- Restricted attachment sites: A smaller number of alveolar-bronchiolar junctions contributes to airflow obstruction and increased airway sensitivity.
- Increased collagen formation: Higher levels of nicotine induce collagen formation in the lung parenchyma, contributing to stiffer, less compliant lung tissue.
Biochemical and Immunological Damage
Exposure to toxins in cigarette smoke during pregnancy is accompanied by multiple biochemical changes in the developing fetal lung, which include effects on lung surfactant production and inflammatory pathways.
- Surfactant deficiency: Research in sheep models suggests that exposure to secondhand smoke during the third trimester reduces the production of surfactant protein A (SP-A), an important protein involved in innate immune defense.
- Increased oxidative stress: Smoking during pregnancy increases oxidative stress in developing fetal lungs. Nicotine and carbon monoxide result in the accumulation of free radicals, unstable molecules that damage cells in the fetus’s lungs. Fetal antioxidant defenses prevail, causing structural, functional and molecular damage.
Other risks of smoking during pregnancy
In addition to affecting the baby’s brain and lungs, maternal smoking causes physiological stress and long-term molecular changes that can negatively affect the baby’s growth and development.
Chronic fetal hypoxia
Since its effects carbon monoxide in the fetus are more pronounced in hemoglobin compared to oxygen, carboxyl becomes abundant in umbilical arteries. therefore, the supply of oxygen to the fetus is hindered. Chronic hypoxia is one of the main causes of intrauterine growth restriction (IUGR) and poor organ development.
Low birth weight
When an expectant woman smokes, toxins are released and prevent the baby from developing properly. Carbon monoxide in cigarettes removes oxygen from the blood, while nicotine, on the other hand, constricts blood vessels, reducing the amount of nutrients that reach the baby. As a result, low birth weight occurs. In addition, developmental problems occur and mortality rates may be higher.
Premature birth
Smoking during pregnancy leads to complications such as placental abruption, in which the placenta detaches from the uterine wall prematurely, and placenta previa, in which the placenta partially or completely covers the cervix. Both conditions may require premature delivery or birth before 37u week. In addition, smokers face the risk of premature rupture of membranes (PPROM), which leads to premature labor.
Conclusion
Maternal smoking has a profound and lasting effect on fetal brain and lung development. Avoiding active and passive smoking is imperative to protect the baby’s respiratory and neurodevelopmental health.
