Pregnancy › Week by Week › Week 20
At 20 weeks you are halfway there. Your baby is about the size of a banana, and this is the week of the big anatomy scan.
Size
A banana
head to heel
Length
10.1 in
about 25.6 cm
Weight
10.6 oz
about 300 g
Your baby at 20 weeks
Halfway made. Your baby is swallowing, growing hair, and getting a first coat of protection for the skin.
Your baby is busy and looking much more like a newborn. They are swallowing small amounts of amniotic fluid, which is good practice for the digestive system, and producing the first stool, called meconium, that will not arrive until after birth.
Skin and hair. Fine hair called lanugo now covers the body, along with a waxy, cheese like coating called vernix caseosa that protects the skin from months in fluid. Hair is starting on the scalp, and the eyebrows are filling in.
Senses and movement. Your baby can hear now, is moving plenty, and has regular cycles of rest and activity. Many people feel those first flutters, called quickening, right around this stretch.
How big is your baby at 20 weeks?
About 10 inches head to heel and roughly 10.6 ounces.
If the length looks like it jumped this week, it did, but not because of a growth spurt. Until now your baby was measured crown to rump, from the top of the head to the bottom, because the legs stay curled up. From around 20 weeks the measurement switches to head to heel, so the number nearly doubles overnight on paper. Your baby did not suddenly double in size.
Your body at 20 weeks
You are at the top of the hill: a real bump, likely first movements, and usually decent energy.
Twenty weeks is often the sweet spot of pregnancy. Your bump is clearly showing, your uterus reaches about level with your belly button, and for many people energy and appetite are steady. If this is a first pregnancy, those first flutters can be easy to miss or mistake for gas, and they get stronger and more regular over the coming weeks.
Common company this week: round ligament pain (a sharp pull on one side when you move quickly), a darkening line down the belly called the linea nigra, mild swelling, and a stuffier nose. Growing out of your regular clothes is very normal now, and comfortable maternity clothes earn their place from about here on.
What is normal, and when to call your provider
Most twinges are normal at 20 weeks, but call your doctor or midwife the same day if you have any of these:
- Regular tightening or cramping, low back or pelvic pressure, or more than four contractions in an hour
- A gush or steady trickle of fluid, or any vaginal bleeding
- A severe or lasting headache, changes in your vision, or sudden swelling of the face and hands
- A noticeable drop in movement once you are regularly feeling your baby
- Burning when you urinate or a fever
Your week 20 checklist
- Go to your anatomy scan and decide beforehand whether you want to know the sex
- Keep taking your prenatal vitamin every day
- Start a short registry list if you feel ready, big items like the stroller and car seat take research
- Try sleeping on your side, a pregnancy pillow helps as the bump grows
- Keep up gentle movement and drink plenty of water
Appointments and tests around 20 weeks
The anatomy scan, a detailed ultrasound usually done between 18 and 22 weeks, is the main event.
The anatomy scan (also called the mid-pregnancy or level 2 ultrasound) is a careful look at how your baby is developing. The sonographer checks the brain, heart, spine, kidneys, stomach, and limbs, measures growth, and looks at the placenta and the amount of fluid. It usually takes longer than earlier scans. If you want to learn the sex and your baby cooperates, this is often when you find out. Most scans are reassuring, and if anything needs a closer look your provider will explain the next steps clearly.
A few things worth having on hand now
A note for your partner
The anatomy scan is a big one, so go if you possibly can. You will see the profile, the hands, the heartbeat, and maybe find out the sex together. If you cannot be there in person, ask whether you can join by video, and be ready to hear every detail after.
You are halfway there
Twenty weeks is a real milestone, the top of the hill with the downhill stretch ahead. However your bump compares to someone else’s, and whenever your first movements arrive, you are in normal, healthy company.
20 weeks pregnant, common questions
Will I find out the sex at the anatomy scan?
Often, yes, if you want to know and your baby is in a cooperative position. It is not guaranteed, since a well-placed leg can hide the view, but the anatomy scan is the most common point to find out.
Why did my baby’s length jump so much this week?
It is a measuring change, not a growth spurt. Up to now length was taken crown to rump with the legs curled. From about 20 weeks it is measured head to heel, so the number nearly doubles at once.
Is it normal to not feel movement yet at 20 weeks?
Yes, especially with a first pregnancy or an anterior placenta (one that sits at the front). Movements are still light and easy to miss this week and become clearer over the next few weeks. Mention it at your scan and have it checked.
What happens if the scan finds something?
Most findings are minor and simply watched. If something needs a closer look, your provider will arrange a follow-up scan or a specialist referral and walk you through the options. A single soft marker on its own is usually not a cause for alarm.
Sources
- American College of Obstetricians and Gynecologists (ACOG), ultrasound and mid-pregnancy care guidance.
- Mayo Clinic, Fetal development: the 2nd trimester.
- MedlinePlus, National Library of Medicine (NIH), Fetal development and prenatal care.
Medical disclaimer: This page is for information and education only and is not a substitute for professional medical advice. Every pregnancy is different. Always follow the guidance of your doctor, midwife, or qualified provider, and contact them with any concerns.