Smart Doctor on Instagram‎: "A beautiful miracle ❤️👶🏻💕 . . . 1. First Trimester (Weeks 1 to 12) Fertilization Occurs when a sperm fertilizes an egg, forming a zygote. Embryo Development The zygote divides and develops into an embryo. By the end of this stage, most major organs are formed. Common Symptoms Include nausea (often called morning sickness), fatigue, and breast changes due to hormonal shifts. 2. Second Trimester (Weeks 13 to 27) Fetal Growth The fetus grows significantly, and the mo