While your baby-to-be still has several weeks to go before she's ready to meet you, she's begun to explore her home inside the womb. All of her senses are beginning to function. Taste buds develop more on her tongue; her ears, now in their final position, can hear more noises; and her eyes may even be open now, perhaps even blinking and closing when she sleeps. She's still much skinnier than she'll be at birth, but she continues to fill out. By the end of this week she'll probably weigh about 1 1/2 pounds.
For the most part you will be unaware of these explorations, but some you might notice — especially your baby's responses to certain noises. For example, you might feel your baby jump in reaction to a loud sound, such as a car horn or your ringing alarm clock. She might wiggle and kick to music (although you won't have any idea whether she's a fan of what she hears or not!). Her movements might also increase when she hears your voice. Most likely, her movements will happen at regular intervals each day. In other words, she might have a schedule, spending time awake and time asleep, just like you do. Hopefully her awake time doesn't fall during your time in bed!
Her sensory experiences and newfound nerve connections also extend to her fingers and toes. She might spend her time wiggling her toes or putting her fingers into her mouth. You might be able to see some of these movements on a sonogram image.
While the nerves around her mouth are becoming sensitive as she prepares to be able to suckle and nourish her own body after birth, you're still nourishing your unborn child via the umbilical cord. (Your blood carries nutrients to your baby through the cord, which consists of a single vein and two arteries.) The umbilical cord is protected against your baby's gymnastics by Wharton's jelly -- a gelatinous goo that keeps the umbilical cord from twisting and knotting as your baby continues to test her muscles and find things to occupy her waking time.
As your baby grows, so does her brain. Deeper grooves and furrows are developing in her cerebral cortex, which is going to be Command Central for many important functions including her ability to see, hear, smell, speak, and walk. Already her brain controls her rhythmic breathing, digestion, and body temperature; these three activities are essential in order for your baby to be able to live outside your body.
Blink-startle response: In fetal development, when the unborn baby responds to loud noises with movement.
Images courtesy of the American Institute of Ultrasound in Medicine (AIUM.org).