About 11 inches long, your baby now weighs a grand total of approximately 1 pound. As he gains weight and moves around, muscles are being strengthened. Air sacs (alveoli) and blood vessels are also developing in the lungs just about now, getting your baby ready to breathe. However, the lungs would still be too immature to do the job on their own if he was born now, mechanical support would be required. Even though he won't actually breathe air until birth, he "practices" by inhaling and exhaling amniotic fluid.
The hearing is also improving. Your baby may begin to grow accustomed to the usual loud noises produced by your body or around your home. Some people believe that listening to music calms a fetus. Certainly, by birth your fetus will have come to recognize your distinctive voice. (It's even been said that babies in the womb who hear a dog bark will be less likely spooked as newborns.)
My What to Expect book says I'm now in my 6th month of pregnancy. I still can't believe how fast time is going. I feel like my belly is growing daily. I need to post some belly pictures soon. Jonathan and I go on Tuesday for my 6th month OB appt. We have a lot to look forward to in the upcoming weeks. Our appt on Tuesday, birthing classes start 2 weeks from Tuesday, our 3D/4D ultrasound around 28 weeks, and us making more progress on the nursery.
We'll keep you updated on how the appointment goes on Tuesday. I hope everyone has a great week!