Pregnancy is the time the future baby spends growing in its mother’s womb: about nine months in humans. The growing baby is first called an embryo, then — once its body plan is laid out, after about two months — a fetus.
Examples
Example 32.5 (The nine-month timetable)
Month 1: a cluster of dividing cells, smaller than a grain of rice, but already growing fast. Month 2: an embryo with the sketch of a head, a beating heart, buds for arms and legs — still smaller than a thumb. Months 3–4: a fetus, complete in plan, that begins to move; the mother soon feels the kicks. Months 5–8: growing and ripening — hearing arrives, and a first coat of hair. Month 9: the baby, usually head-down and around , is ready.