Which of the following structures develops first during the period of the embryo?
Learn how your baby is conceived and how your baby develops inside the mother's womb. WEEK BY WEEK CHANGES Gestation is the period of time between conception and birth when a baby grows and develops inside the mother's womb. Because it's impossible to know exactly when conception occurs, gestational age is measured from the first day of the mother's last menstrual cycle to the current date. It is measured in weeks. This means that during weeks 1 and 2 of pregnancy, a woman is not yet pregnant. This is when your body is preparing for a baby. A normal gestation lasts anywhere from 37 to 42 weeks. Week 1 to 2
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Zygote; Blastocyst; Embryo; Fetus Feigelman S, Finkelstein LH. Assessment of fetal growth and development. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 20. Ross MG, Desai M, Ervin MG. Fetal development, physiology, and effects on long-term health. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 2. Updated by: John D. Jacobson, MD, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. |