Final answer:
The newborn's gestational age can be assessed through the observation of skin appearance, lanugo amount, plantar creases, pinna structure and recoil, and genital development. These indicators reflect the physical maturity levels of the newborn.
Step-by-step explanation:
The essential aspects in the assessment of a newborn's gestational age include the appearance of the skin, the amount of lanugo, and the development of plantar creases, the formation and recoil of the pinna, and the development of genitalia. These physical characteristics, along with others, are part of a comprehensive evaluation used to estimate a newborn's maturity and potential healthcare needs. The vernix caseosa, a waxy substance that coats the skin of the fetus, and the fine, silky hair called lanugo, which covers the skin typically between weeks 17-20, will shed as the fetus grows. The physical assessment will include checking the amount of subcutaneous fat, the texture and appearance of the skin, and the presence of vernix and lanugo. The existence and depth of plantar creases on the soles of the feet can also indicate maturity, as they are more prominent in full-term infants. Additionally, the structure and firmness of the breast tissue, the positioning and structure of the ears, and the development of the external genitalia are evaluated. Therefore, the correct answer to the question of which aspects are essential in the assessment of a newborn's gestational age would be: D) Lanugo amount, pinna recoil, and genitalia development.