Pregnancy Timeline By Folzie3313 Feb 1, 2011 Month 1 A simple functioning circulatory system has developed in the embryo. The spinal cord is closed and the embryo is 4mm long. Mar 1, 2011 Month 2 The nervous system and the motor activity has begun to develop. The cardiac valves and also the four chambers of the heart are established and functioning. Apr 1, 2011 Month 3 The baby weighs 3/4 of an ounce and the baby can also flex its little arms and legs. May 1, 2011 Month 4 The baby is six inches long and has fully shaped hands and feet with nails. Jun 1, 2011 Month 5 The baby's hair starts to appear and also reacts to sounds. Jul 1, 2011 Month 6 The baby is over twelve inches long and the thumb is able to grasp. Aug 1, 2011 Month 7 From now until birth, the baby triples in weight and grows thirteen to twenty inches. Sep 1, 2011 Month 8 The baby's lungs are maturing and learns the breathing cycle. Oct 1, 2011 Month 9 Welcome baby! Delivery happens usually between 38-42 weeks.