Week 14. Beginning the second trimester, fetuses start growing at different paces, some faster than others, some more slowly. Despite the differences in growth rates, all babies in utero follow the same developmental path.
This week, the path is leading your baby – who is about the size of your clenched fist – toward a straighter position as the neck is getting longer and the head more erect. And on top of that cute little head, your baby might actually be sprouting some hair.
Eyebrow hair is also filling in about now, as is body hair, called lanugo. Don’t worry, it’s not permanent. This downy coating of hair is there to keep your baby warm for now – like a furry blanket.
As baby fat accumulates later on in your pregnancy, most of that hair will be shed – though some babies, especially those born early, still have a temporary fuzzy coating at delivery.
Week 15. Your baby, who measures four and a half inches this week and weighs around 2 to 3 ounces, is about the size of a naval orange. Looking more and more like the baby you’re picturing in your dreams, his or her ears are positioned properly on the sides of the head, and the eyes are moving from the side of the head to the front of the face.
By now your baby has the coordination, strength, and smarts to wiggle his or her fingers and toes and even suck a thumb. But that’s not all your baby can do now. He or she can also breathe (or at least make breathing movements), suck, and swallow – all in preparation for the big debut and life outside the womb.
And though it’s unlikely that you’ll be feeling the movements from your little one this week, your baby is certainly getting a workout – kicking, flexing, and moving those arms and legs.
Week 16. With a whopping weight of anywhere from 3 to 5 ounces and a length (crown to rump) of 4 to 5 inches, your baby is growing up fast. Muscles are getting stronger, especially the back muscles, enabling your little one to straighten out even more.
Your baby-to-be is looking more and more adorable, with a face that has eyes (complete with eyebrows and eyelashes) and ears in the right spots. What’s more, those eyes are finally working! Yes, it’s true: Your baby’s eyes are making small side-to-side movements and can even perceive some light, though the eyelids are still sealed.
Your baby is also becoming more sensitive to touch. In fact, he or she will even squirm if you poke your belly (though you probably won’t be able to feel those squirms just yet).
Week 17. Take a look at your hand. Your baby is about a palm-size now, with a crown-to-rump length of 5 inches and an approximate weight of 5 (or more) ounces. Body fat is beginning to form (baby’s fat, that is, though yours is probably forming pretty quickly these days, too), but your little one is still quite skinny, with skin that is practically translucent.
This week, your baby is all about practice, practice, practice in preparation for birth. One important skill your baby is sharpening now : sucking and swallowing - to get ready for that first (and second…..and third) suckle at breast or bottle.
Your baby’s heart rate is regulated by the brain (no more spontaneous beats) and clocks in at 140 to 150 beats per minute (roughly twice your own heart rate).