At week 16, the fetus reaches a length of about 6 inches, makes active movements, and makes sucking motions with the mouth.
Review Date 6/30/2019
Updated by: John D. Jacobson, MD, Professor of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda Center for Fertility, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.