The first trimester of a pregnancy is a time of incredible growth and development. A 7-week fetus will have begun to develop all essential organs.
Review Date 4/1/2023
Updated by: John D. Jacobson, MD, Professor Emeritus, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.