What Your Baby Hears
Amazingly, babies begin to respond to sound at around five months. We know from ultrasound techniques and heart-rate measurements.

When she hears a sudden noise, like a firecracker, your baby will blink and hold still for a moment. Her heart rate will decrease. She's listening. She acquires this new skill when her inner ear, or cochlea, begins to function.

Experts aren't sure if or how long your baby will remember prenatal sounds. But many parents believe that the stories or lullabies their babies heard frequently in the womb are comforting. When heard again after birth.

What are Borborygmi?
Your baby lives in a noisy environment. The sound level in the uterus can reach 70 decibels. Some people compare the sounds of the womb to those of a vacuum cleaner.

Doctors call the loud, swishing sounds of your intestines borborygmi. This month your baby will begin hearing borborygmi. Also the noise of your heart. Your tummy rumblings. And the vibrations of your voice. A full month before her birth, your baby will start making sense of these sounds, distinguishing between music, heartbeats and conversation.

First Flutters
Your baby's movements will become smoother and more coordinated this month. She may try sucking her thumb for the first time. She'll also hiccup a lot, as she practices the movements that will allow her to breathe air outside the womb.

Don't ignore the feeling of butterflies in your stomach. It may be quickening. The first time you can actually feel your baby's movements.

Growth Update
By the end of this month, your baby will pass the one-pound mark. She'll be between 10-12 inches long. Her heartbeat will be loud enough to hear with an ordinary stethoscope. Ask your doctor if you can listen for yourself.