Your baby doesn't have much room to maneuver now that he's over 18 inches long and tips the scales at 5 1/4 pounds (pick up a honeydew). Because it's so snug in your womb, he isn't likely to be doing somersaults anymore, but the number of times he kicks should remain about the same. His kidneys are fully developed now, and his liver can process some waste products. Most of his basic physical development is now complete – he'll spend the next few weeks putting on weight.
Your baby now weighs about 4 3/4 pounds (like your average cantaloupe) and is almost 18 inches long. His fat layers – which he'll need to regulate her body temperature once he's born – are filling her out, making him rounder. His skin is also smoother than ever. His central nervous system is maturing and his lungs are continuing to mature as well. If you've been nervous about preterm labor, you'll be happy to know that babies born between 34 and 37 weeks who have no other health problems generally do fine. They may need a short stay in the neonatal nursery and may have a few short-term health issues, but in the long run, they usually do as well as full-term babies.
This week your baby weighs a little over 4 pounds (Think pineapple) and has passed the 17-inch mark. He's rapidly losing that wrinkled, alien look and his skeleton is hardening. The bones in his skull aren't fused together, which allows them to move and slightly overlap, thus making it easier for him to fit through the birth canal. These bones don't entirely fuse until early adulthood, so they can grow as his brain and other tissue expands during infancy and childhood.