Final answer:
Exposure to toxic substances during pregnancy can cause birth defects, such as neural tube defects and anemia. Certain chemicals, like pesticides and hair dye, may be associated with birth defects, but evidence is lacking. Nutritional deficiencies, radiation exposure, and certain chemical compounds are suspected teratogens.
Step-by-step explanation:
Exposure to toxic substances during pregnancy can cause birth defects, such as neural tube defects and anemia. Some chemicals, like certain pesticides, have been associated with birth defects, but there is no evidence that using hair dye during pregnancy increases this risk. Prescription drugs and nutrient deficiencies, as well as chemical compounds like methyl iodide and bisphenol A, are suspected teratogens. Radiation from diagnostic X-rays or radiation therapy and nutritional deficiencies can also cause mutations in embryonic germ cells and lead to birth defects.
Lead exposure during pregnancy can cause impaired growth, impaired neural development, low birth weight, spontaneous abortion, and stillbirth. However, a maternal diet lacking certain nutrients, like folic acid, can also cause birth defects. It has been shown that a small, daily dose of folate given to women during pregnancy reduces the incidence of spinal cord malformation birth defects by 40%.