Pregnancy and Human Development Pregnancy and Human Development From Egg to Embryo Pregnancy - events from fertizilation until birth. Conceptus - the developing offspring. Gestation period - from the last menstrual period until birth. Preembryonic development lasts from fertilization through the first 2 weeks of development; the conceptus is known as a preembryo. The 3rd through 8th weeks after fertilization is the embryonic p.. 2014. 11. 8. 이전 1 다음