TL;DR
- Your baby is about 26.7 cm — the size of a carrot.
- Baby is swallowing amniotic fluid to practice digestion.
- You may notice Braxton Hicks contractions starting.
- Start thinking about a baby registry to organize what you'll need.
Your Baby This Week
At 26.7 cm, your baby is the length of a carrot and getting busier by the day. One of the key activities this week is swallowing — your baby is gulping down amniotic fluid on a regular basis. This isn't just random swallowing; it's practice for the digestive system. The fluid passes through the stomach and intestines, giving these organs a trial run before they need to process milk after birth.
Your baby's taste buds are now functional enough to detect flavors in the amniotic fluid. Research suggests that what you eat can influence the taste of the fluid, and babies show preferences for sweet flavors over bitter ones. So when you eat that fruit or have a piece of chocolate, your baby may be tasting a hint of it too.
The bone marrow is now mature enough to take over blood cell production, a job previously handled by the liver and spleen. This is a significant developmental milestone, even though it happens quietly behind the scenes.
Your baby's movements are becoming more coordinated and stronger. You might notice patterns — more active after you eat, or kicking up a storm when you lie down at night. These movements are not only normal, they're a sign that your baby is healthy and developing well.
Your Body This Week
Your belly is unmistakably pregnant now, and you might be getting used to the new shape of your body. The top of your uterus is about an inch above your belly button, and it will continue to rise about a centimeter per week.
Braxton Hicks contractions might start appearing around now. These are your uterus's way of warming up for labor. They feel like a tightening or hardening of your belly that lasts for 30 seconds to a minute, then releases. Unlike real contractions, Braxton Hicks are irregular, don't get closer together, and usually aren't painful — just uncomfortable or surprising.
Stretch marks may be appearing on your belly, breasts, hips, or thighs. About 90% of pregnant people develop them to some degree. While no product can prevent them entirely (they're largely genetic), keeping skin well-moisturized can ease the itching that comes with stretching skin.
Your appetite is probably healthy right now, and cravings might be in full swing. It's fine to indulge occasionally, but try to focus on nutrient-dense foods that support your baby's growth. Iron is especially important during the second trimester as your blood volume continues to increase.
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Common Questions at Week 21
What are Braxton Hicks contractions?
Braxton Hicks are irregular, usually painless contractions that begin in the second trimester. Think of them as practice contractions. They typically go away when you change position, drink water, or rest. If contractions become regular, painful, or are accompanied by other symptoms, contact your provider.
How much water should I be drinking?
Aim for about 8-12 cups of water per day during pregnancy. Staying hydrated helps with amniotic fluid levels, blood volume, constipation, and swelling. If your urine is pale yellow, you're likely drinking enough.
When should I start taking a childbirth class?
Many people start childbirth education classes between weeks 24-30, so now is a good time to research your options. Classes are offered through hospitals, birthing centers, and online. They cover labor stages, pain management options, breathing techniques, and what to expect postpartum.
This Week's Tip
Start thinking about a baby registry. You don't need to complete it all at once — just begin with the basics. A registry helps you organize what you'll actually need (and avoid duplicates from well-meaning gift-givers). Start with essentials: a safe sleep space, a car seat, diapers, and basic clothing. You can add to the list over the coming weeks as you learn more about what you'll want. Many stores and websites offer completion discounts on registry items you end up buying yourself.
Sources
- American College of Obstetricians and Gynecologists (ACOG). How Your Fetus Grows During Pregnancy.
- Mayo Clinic. Fetal Development: The 2nd Trimester.
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