How’s My Baby Growing? Fetal Development From 21-24 Weeks

pregnant-coupleYou are thoroughly in the midst of the “golden” period of pregnancy where many women find themselves with more energy, less symptoms and increased appetite. Plus, Baby will most likely break the one-pound mark during these next four weeks, which is cause for celebration. Here’s the weekly guide to what’s happening in utero. Note that these are general guidelines for the average fetus, and every baby’s rate of growth is different.

Week 21 

Baby is big enough now that you can feel him move—watch as those initial flutters turn into full out nudges and kicks. He measures 10.5 inches and weighs over 12 ounces (like a pomegranate). His skin begins to be covered by a layer of vernix caseosa, a fatty substance that acts as a waterproof barrier to keep Baby’s skin from drying out. His bone marrow starts to make blood cells, and he now absorbs sugar from swallowed amniotic fluid.

Did you know the taste of amniotic fluid varies depending on what you’ve eaten? Research shows that babies are more likely to eat what they’ve previously “tasted” in the womb—good reason to eat a varied and healthy diet during pregnancy.

Week 22 

By this time you should be able to hear Baby’s heartbeat with a stethoscope instead of the Doppler monitor. She measures about 11 inches head to heel and weighs 14 ounces (like a papaya). With her eyebrows, eyelids and lips more developed, Baby begins to resemble a newborn. Although her eyes will remain fused shut for several more weeks, she can still differentiate between light and darkness. Her mouth is busy with tooth buds forming beneath the gums and taste buds on the tongue. Her skin has deep creases. She can react to loud sounds or sudden movements from you or even to light pressure on your abdomen.

Give some thought to creating your Birth Plan, a list of preferences for labor and delivery. How long past your due date are you comfortable with? Do you wish to try natural induction techniques first? Are you averse to using certain medications? What position would you prefer to give birth in? While everything may not go according to plan, it’s always good to review your options ahead of time.

Week 23 

Baby measures just over 11 inches head to heel and weighs about one pound (like a grapefruit). His face is fully formed, and skin pigmentation begins to emerge. His proportions are more like a newborn’s in that his head is no longer half his total length. Developing organs include the pancreas and the blood vessels in his lungs. The bones in his middle ear harden and his sense of balance develops so that he can feel you exercising.

Are you exercising? Always check with your doctor first, but there are plenty of safe options for exercising in the second trimester including walking, strength training, swimming and prenatal pilates.

Week 24

Baby measures 12 inches head to heel and weighs a little over one pound (like a cantaloupe). Her translucent skin becomes more opaque and pinkish due to the formation of capillaries. And she’ll soon begin to plump up—at the rate of about three ounces per week—as fat starts to form on her tiny body. The lungs continue to develop, producing surfactant, a dish soap-like substance that enables the air sacs to expand once she’s born. Muscle coordination of the hands improves enough that she can even suck her thumb. Sometime between week 24 and 28, your doctor will schedule a glucose screening test for gestational diabetes.

This is also a great time for planning a babymoon – a mini getaway for your and your partner before Baby arrives on the scene. Weeks 14 to 28 are considered the best time for travel while you feel your best and miscarriage or premature birth risks are at their lowest. Bring along this TSA-sized travel kit of organic pregnancy skin care products.

What’s next? Read about your baby’s fetal development from 25-28 weeks.

Got questions or ideas for future blog posts? Leave a comment below!

Donna DeForbes is a writer, designer and the force behind, a blog that explores ways to make going green fun and easy for the whole family. She is the author of the e-book, “The Guilt-Free Guide to Greening Your Holidays.” Follow her on Facebook and Twitter.

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  1. How’s My Baby Growing? Fetal Development From 17-20 Weeks | Life'n Stats - June 29, 2013

    […] What’s next? Read about your baby’s fetal development from 21-24 weeks. […]

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