1. What is formaldehyde? Formaldehyde is a toxic and harmful substance that is commonly found in building materials, furniture and other decoration materials. It has a pungent odor and has a non-negligible impact on human health. 2. Pregnant women are susceptible to the harm of formaldehyde. Pregnant women have weak immunity during pregnancy and are easily affected by environmental pollutants. Formaldehyde is a volatile organic compound that easily enters the human body through the respiratory tract, causing harm to pregnant women. 3. The impact of formaldehyde on the fetus. After formaldehyde enters the body of a pregnant woman, it will be transmitted through the blood circulation.