Final answer:
The most significant risk for adolescent mothers during pregnancy is the birth of premature babies, due to the additional physical demands on their still-developing bodies.
Step-by-step explanation:
During the embryonic and fetal stages of pregnancy, the developmental risk for adolescent mothers is primarily the potential for giving birth to premature babies (D). Adolescents are still growing and developing themselves, which can put unique stresses on their bodies during pregnancy. This may contribute to an increased risk of preterm labor and delivery, leading to babies being born before their bodies are fully prepared to handle life outside the womb. Premature birth can result in various health problems for the infant, including respiratory, cognitive, and developmental issues.
It is critical during these stages of pregnancy to avoid teratogens, which are substances like alcohol, drugs, and certain medications that can disrupt fetal development. For example, alcohol exposure can result in fetal alcohol spectrum disorders (FASD), leading to physical and cognitive impairments for the child that persist into adulthood. Hence, prenatal care is essential, which includes receiving proper nutrition and avoiding substances that can be harmful to the embryo or fetus.