Return to Fetal Development Overview

• Amniotic fluid is at its highest level during your pregnancy.
• Your baby's head size has increased 3/8ths of an inch due to rapid brain growth.
• Neurons and synapses are developing in huge numbers -- forming connections in your baby's brain will give him the skills he needs to thrive as a newborn. This week, he may be able to coordinate sucking and swallowing with breathing.
• While most of his bones are hardening, his skull is quite pliable and not completely joined. The bones will be able to move slightly to make birthing easier.
• You baby takes intermittent deep breaths -- of water! That's okay, though since she gets oxygen from the placenta. This breathing exercises muscles and encourages her lung cells to produce more surfactant (a protein essential for healthy lung development).
• If your baby is a boy, his testicles will be descending from his abdomen into his scrotum. Sometimes one or both testicles won't move into position until after birth.
• Your infant is now 17.2 inches (43.7cm) long and weighs 4.23 pounds (1918gm).