Last week, your baby stopped being a fetus and graduated to an embryo! Baby-to-be is looking more and more like a newborn. Her nose is adding definition, while her ears are moving into place farther back on her head and her eyes are moving farther apart. Even though her eye lenses and eyelids are formed, she'll keep them shut until week 27. Still, her head overwhelms the rest of her body. In fact, her head makes up nearly half of her crown-rump measurement (CRL). Don't worry—that's about to change. In the coming weeks she'll experience a growth spurt.
Along with other organs developing in her body, baby-to-be's genitalia are beginning to form this week too. By the end of the week, her (or his!) body parts will have formed into either a clitoris and labia majora or a penis. While you might be anxious to find out whether you're having a boy or a girl, the sonographer won't be able to tell at this point.
Your baby is starting to have sleeping and waking cycles, usually between 5 and 10 minutes long. You might even wake her if you cough! Your baby's body and limbs are now growing faster than her head, and she looks more and more like a tiny person.
With a live image of your growing baby-to-be, you'd be able to see her wiggle and kick and make all sorts of movements with her arms and legs, which are becoming longer each day. The bones inside are becoming stronger and harder as the skin on the outside develops more layers (but it's still translucent). Despite all this movement, your baby-to-be is barely 1-1/2 to 2 inches long and only weighs 1/4 of an ounce. You won't be able to feel her jerky gestures just yet, but as she adds more weight and strength you should be able to feel her movements soon.
What else is happening? Your baby's organs are finalizing their shapes and functions. The development of her lung tissue is nearly complete, and although your circulatory system is still bringing nutrients and oxygen to your baby, her own blood supply is starting to get into the act. Meanwhile, glands in her pancreas are producing insulin and starch, and her intestines are starting to form folds in preparation for the day she'll digest food on her own.
Your baby's skin is starting to thicken as it acquires layers and becomes more opaque. Tiny hair follicles are appearing below the surface of her skin. Her jaw is starting to harden, and she has her first tooth buds, which will grow into tiny baby teeth. Her vocal cords are beginning to form too.
Terms to Know
Images courtesy of the American Institute of Ultrasound in Medicine - AIUM.org