Week 20: The Anatomy Scan

The Quick Brief

You're halfway there. Week 20 brings the anatomy scan—the most comprehensive ultrasound of the pregnancy. This is the appointment where specialists check every organ system and you can find out the sex if you want. This one matters. Be there.

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What's Happening with Baby

Your baby is now about the size of a banana (6.5 inches from head to rump, about 10 ounces). They're developing at a remarkable pace, and this week's anatomy scan exists specifically to verify that everything is on track.

The brain is developing specialized areas for the senses—taste, smell, hearing, sight, and touch. Neurons are multiplying at a rate of 250,000 per minute during peak development periods. The baby is covered in vernix caseosa, a waxy white coating that protects the skin from constant amniotic fluid exposure (imagine being in a bath for months—you'd wrinkle beyond recognition without some protection).

Your baby now has a sleep-wake cycle, though it's not synced to yours. They'll often be most active when mom is trying to rest, because her movement during the day rocks them to sleep. Underneath the vernix, a fine layer of hair called lanugo covers the body, helping the vernix stick to the skin. This will mostly shed before birth.

If you're finding out the sex, this is typically when it's possible to tell visually. The external genitalia are developed enough to be visible on ultrasound, though position matters—a stubborn baby with crossed legs might not cooperate.

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What's Happening with Mom

By week 20, the uterus has reached the belly button level and will grow about a centimeter per week from here. The pregnancy is unmistakably visible, which brings a new social dynamic—strangers may start commenting on her body.

Physical symptoms at this stage include leg cramps (often at night, caused by the extra weight and pressure on blood vessels), continued back pain, and possibly the start of Braxton Hicks contractions—practice contractions that are irregular and shouldn't hurt. Her body is literally rehearsing.

Heartburn often intensifies as the growing uterus pushes against the stomach. The hormone relaxin (which loosens joints in preparation for delivery) can cause clumsiness and increased risk of rolling ankles. Shortness of breath is common because the lungs have less room to expand fully.

Emotionally, week 20 can be complicated. It's an official milestone—halfway—but it can also trigger anxiety about all that remains. The anatomy scan, while usually reassuring, is specifically looking for problems, which can feel stressful even when everything is fine.

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What Dad Should Do This Week

1. Be at the Anatomy Scan

Clear your calendar. This is the appointment. It typically takes 30-45 minutes because the sonographer is checking brain structure, spine alignment, heart chambers, kidney function, limb development, and dozens of other measurements. You'll see your baby in detail you haven't seen before. If something is concerning, you'll want to be there. If everything is perfect, you'll want to have shared that moment.

2. Prepare Questions in Advance

The sonographer is focused on measurements and may not explain much. Have questions ready. Is everything measuring on track? Are there any concerns? Is the placenta positioned normally? What does amniotic fluid level indicate? Don't be afraid to ask for clarification—this is your appointment too.

3. Have the Sex Conversation Before the Scan

Decide before you walk in: Do you want to know? If you disagree, work that out ahead of time. If you both want to know but want to tell family at a gender reveal, ask the sonographer to write it down and seal it in an envelope. If you don't want to know, tell them immediately so it doesn't slip during the scan.

4. Process Together Afterward

After the scan, get lunch or coffee together. Don't just rush back to work. This is a lot of information and potentially a lot of emotions. Talk about what you saw. What surprised you? What are you thinking about? The anatomy scan makes the baby real in a way that nothing else has yet.

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The Relationship Check-In

The anatomy scan can be overwhelming regardless of results. If everything looks good, there's relief mixed with the growing reality that this is happening. If there are any concerns or need for follow-up, that brings its own stress.

Your job this week: Follow her lead on processing. Some people need to talk it through immediately. Others need time to sit with information. Ask "How are you feeling about everything?" and then actually listen. Don't try to fix or reassure prematurely. Sometimes people just need to voice their thoughts and feel heard.

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What's Coming Up

Weeks 21-24 are prime action time. Energy is still relatively high, mobility is still good, and the third-trimester exhaustion hasn't set in. If you have projects to complete before the baby arrives—nursery, home repairs, car upgrades—the next month is your window. Week 24 is the viability milestone, which brings its own emotional weight. Start thinking about hospital tours and childbirth classes; spots fill up.

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Quick Reference Box

Sources: Cleveland Clinic Fetal Development, March of Dimes Week by Week, NIH Pregnancy Facts