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How do a full-term baby’s body proportions differ from those of an earlier fetus?

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At full term (38 weeks), a baby’s body is characterized by a plump appearance with improved proportions compared to an earlier fetus. While the head remains large and the lower limbs are still slightly shorter than the upper limbs, the body and limbs are better-rounded.1

In contrast, an earlier fetus—such as one observed at six months—typically has a lean body with wrinkled, reddish skin. Throughout the stages of prenatal development, the fetus undergoes significant changes in proportion; for instance, during the third month, the head is disproportionately large. As development progresses toward full term, the skin loses its coat of lanugo hair, and fat deposits beneath the skin help smooth out wrinkles, contributing to the more rounded, plump physique observed at birth.1