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  • Julie Bos

Getting Ready for Baby’s Birth - Your Baby’s Development in the Third Trimester

You’re almost there – but your baby still has plenty of growing to do in your third trimester.

And it can feel like the longest of the trimesters as you anticipate your baby’s arrival, your belly continues to grow, and your baby really begins practicing kicking and rolling.

Your baby is really busy in these final weeks as they wrap up their fetal development. Not only are they growing in length and weight, but they’re also putting the final touches on their brain and lung development as they prepare for life outside the womb.

Here’s what to expect in the final weeks of your pregnancy – the third trimester is finally here!

Baby Development Highlights

The third trimester lasts from week 28 to birth. It’s the only trimester that doesn’t have a set end date since most women won't end up giving birth on their due date.

Your baby grows a low this trimester, gaining lots of weight and taking up more space in your belly.

Did you know that starting around week 30, your baby will begin to put on half a pound a week until they are born? But don’t be alarmed! This weight gain is essential to their final phase of development and transition to life outside the womb.

Here are some highlights of your baby’s development in the third trimester:

· Brain: Your baby’s brain is growing faster than ever, as it takes on full responsibility for managing organs and doing new tricks, like dreaming and regulating body temperature.

· Bones: In the third trimester, your baby’s bones will harden. Their head bones will not be fused yet to allow an easier pass through the birth canal, and won’t solidify until well after your child’s first birthday.

· Lungs: Their lungs are fully developed but are aggressively practicing breathing in amniotic fluid in preparation for breathing air. Each week that passes makes your baby’s lungs stronger – for their first breath and all those baby coos and cries.

· Digestive System: In the final weeks of pregnancy, your baby will produce their first poop, called meconium, which is made up of fluids, cells, vernix, and lanugo swallowed from amniotic fluid.

· Senses: From weeks 29-31, your baby will begin to get signals from all their senses. They especially love the sound of your voice!

· Hair, Skin, and Nails: In the third trimester, your baby’s skin will become opaque from fat accumulation. They will shed their vernix (waxy coating) and lanugo (hairy coat) as they gain more weight.

You’re so close to meeting your baby! As your pregnancy comes to a close, try your best to power through these final weeks by taking care of yourself.

At LivingWell Pregnancy Centers, we care about you and your growing baby. That’s why we offer free women’s wellness checkups, pregnancy tests, your first ultrasound, and endless education and resources.

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