What substance found in cigarettes can harm fetal development?

Nicotine is a significant substance found in cigarettes that can harm fetal development. When a pregnant person smokes, nicotine passes through the placenta and can adversely affect the developing fetus in several ways. It restricts blood flow to the placenta, which can decrease the oxygen and nutrient supply to the fetus. This can lead to various complications, such as low birth weight, preterm birth, and developmental delays. Additionally, nicotine exposure in utero is associated with increased risks of sudden infant death syndrome (SIDS) after birth and long-term neurodevelopmental issues.

While carbon monoxide, tar, and formaldehyde are also harmful substances found in cigarette smoke, they primarily contribute to different health risks. Carbon monoxide reduces the blood's ability to carry oxygen, tar primarily contributes to lung damage, and formaldehyde is a known irritant and carcinogen. However, nicotine stands out for its direct and specifically harmful effects on fetal growth and development, making it crucial to address in discussions about smoking during pregnancy.