At 20 weeks pregnant you are halfway there: about 4 1/2 months along, in the second trimester, with about 20 weeks to go until your estimated due date.
At 20 weeks pregnant you have reached the middle of the road: many people feel first flutters around now, and the anatomy ultrasound gives you a detailed look at your baby.
Every clinical detail below was read in October 2026 on the primary sources named, and where they disagree we print both.
Key Takeaways
20 weeks is the halfway point: about 4 1/2 months, 18 weeks after conception (Mayo Clinic), with about 20 weeks to go.
Mayo Clinic lists about 6 1/3 inches crown to rump and about 11 ounces. The Office on Women’s Health says about 6 inches and 9 ounces.
Cleveland Clinic says first movements come around 16 to 20 weeks, and in a first pregnancy often not until 20 weeks.
The anatomy ultrasound happens around 18 to 22 weeks. Learning the sex is your choice.
Bleeding, leaking fluid, severe belly pain, a headache that won’t go away or vision changes are reasons to seek care right away.
Table of Contents
20 Weeks Pregnant at a Glance
Quick Answer
At 20 weeks pregnant you are at the halfway point (Mayo Clinic, Office on Women’s Health): about 4 1/2 months along, in the second trimester, with about 20 weeks to go. Mayo Clinic lists the baby at about 6 1/3 inches crown to rump and about 11 ounces, and the anatomy ultrasound happens around 18 to 22 weeks (Cleveland Clinic).
20 weeks pregnant
What to know
Trimester
Second on every definition we checked: 14 weeks 0 days to 27 weeks 6 days (American College of Obstetricians and Gynecologists, ACOG, via UPMC), or week 13 to week 28 (Office on Women’s Health).
Month
About 4 1/2 months, so you are finishing your 5th month. This counts 4 weeks and a few days per month. Months are a convention, not a medical unit.
Weeks to go
About 20 (40 minus 20, counted from the first day of your last menstrual period).
Baby’s size
About 6 1/3 inches (160 mm) crown to rump and about 11 ounces (320 g), per Mayo Clinic. The Office on Women’s Health says about 6 inches and about 9 ounces.
Common symptoms
Heartburn, sore back and hips, stretch marks, swelling of the ankles and fingers, leg cramps at night.
This week’s care focus
The anatomy ultrasound, noticing your baby’s first movements, and side sleeping.
20 weeks pregnant: quick facts with sources.
How the weeks are counted. The Office on Women’s Health says pregnancy lasts about 40 weeks, counting from the first day of your last normal period, not from conception. Mayo Clinic notes you are not actually pregnant for the first week or two of that timeline, so it describes week 20 as 18 weeks after conception. If your provider changed your due date after an early ultrasound, go by your adjusted dates.
Your Baby’s Development at 20 Weeks
Here is what the sources tie to week 20 and nearby weeks.
Source and timing
What it says is happening
Mayo Clinic, week 20 (18 weeks after conception)
You might be able to feel your baby’s movements, called quickening. The baby sleeps and wakes regularly and can be woken by noise or by your movements.
Office on Women’s Health, week 20
The baby is more active. Fine, downy hair called lanugo and a waxy coating called vernix cover the body. Eyebrows, eyelashes, fingernails and toenails have formed. The baby can hear and swallow.
Mayo Clinic, week 18
The ears start to stand out on the head, hearing is starting to develop, and the digestive system has begun working.
Mayo Clinic, week 19
Growth slows. A greasy, cheeselike coating called vernix caseosa begins to cover the skin. The baby is releasing urine, which now makes up most of the amniotic fluid.
Fetal development around week 20, by source.
Can your baby hear you at 20 weeks? The Office on Women’s Health says that by week 20 your baby can hear. Mayo Clinic puts the start of hearing development at week 18.
How Big Is Your Baby at 20 Weeks?
Two primary sources give a week 20 figure, and they do not match, so both are printed.
Source
Week
Length
Weight
Mayo Clinic
20
About 6 1/3 inches (160 mm), crown to rump
About 11 ounces (320 g)
Office on Women’s Health
20
About 6 inches
About 9 ounces
Mayo Clinic
22
About 7 1/2 inches (190 mm), crown to rump
About 1 pound (460 g)
Office on Women’s Health
24
About 12 inches
About 1 1/2 pounds
Baby size near 20 weeks. Sources differ, so both are printed.
Why the numbers differ. Mayo Clinic measures crown to rump, which does not include the legs. The Office on Women’s Health does not say how it measures. We have not converted either set, and found no fruit comparison for week 20 on a primary source. Healthy babies vary.
20 Weeks Pregnant Symptoms
UPMC says morning sickness, fatigue and mood swings usually fade by the second trimester, and that you should talk to your doctor if morning sickness continues. You may have many of the changes below or only a few.
Symptom
What the sources say
What may help
Heartburn
UPMC says it may start earlier but ramps up in the second trimester.
Avoid a big meal close to bedtime (MedlinePlus).
Sore back and hips
UPMC says hormones and weight gain can throw you off balance, and long sitting or standing may cause back pain.
Low-impact exercise such as walking or swimming (UPMC), and side sleeping with pillows (MedlinePlus).
Leg cramps
MedlinePlus notes a leg cramp can wake you at night.
If a cramp wakes you, press your feet hard against the wall or stand on the leg (MedlinePlus).
Swelling
The Office on Women’s Health lists swelling of the ankles, fingers and face.
Mention it at your visit. Extreme swelling of the hands or face is urgent (CDC).
Common symptoms at 20 weeks pregnant.
Other changes. The Office on Women’s Health also lists stretch marks, back, groin and thigh aches, darker skin around the nipples, a line from the belly button to the pubic hairline, darker patches on the face, numb or tingling hands, and itching on the abdomen, palms and soles. Tell your provider about itching.
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A 20 weeks pregnant belly can look very different from one person to the next, and bumps vary a lot at the same week. For the usual progression, see pregnant belly by month.
Where your uterus is now. Cleveland Clinic says that by 20 weeks the fundus, the top of your uterus, is at your belly button. Fundal height, the distance from there to your pubic bone, is measured beginning about 20 weeks (UPMC says around week 24). In centimeters it should roughly match your number of weeks, plus or minus 2, from about weeks 20 to 36. Measuring ahead or behind can have many causes, including a wrong due date, and an ultrasound is the more accurate check if there is a concern.
Feeling your baby move. Cleveland Clinic says quickening, the first movements you feel, happens around 16 to 20 weeks. If you have been pregnant before you may notice it by about 16 weeks, but in a first pregnancy it is common not to feel movement until 20 weeks. It can feel like fluttering, tapping or bubbles popping.
Not feeling anything yet? Cleveland Clinic says an anterior placenta, one that sits between your uterus and your belly, can make the first movements harder to feel, and that you should generally feel some movement by 20 to 24 weeks. Talk to your provider if you are concerned. Cleveland Clinic’s kick count target of 10 movements in two hours applies from the third trimester (28 weeks).
Prenatal Care, Tests and Appointments Around Week 20
UPMC says second trimester prenatal visits are usually every four weeks. The big event now is the anatomy ultrasound, often called the 20 week scan.
What
When
Details
Source
Anatomy ultrasound
Around 18 to 22 weeks
A detailed look at the fetus, placenta and amniotic fluid. Takes around 45 minutes.
Cleveland Clinic, UPMC
Quad screen
Between 15 and 22 weeks
A blood screening test, if you are having it and have not had it yet.
UPMC
Glucose screening
Between weeks 24 and 28
An oral glucose screen. Coming up next.
UPMC
Flu and COVID-19 vaccines
During respiratory virus season
Your provider will offer any vaccines.
UPMC
Tests, scans and vaccines around 20 weeks, as read in October 2026.
What the 20 week ultrasound checks. Cleveland Clinic lists the fetal heart, brain, spine, kidneys and bladder, limbs, hands and feet, face, chest and lungs, stomach and intestines, heart rate, umbilical cord blood flow, placenta position, amniotic fluid, and your uterus, ovaries and cervix.
Limits of the scan. Cleveland Clinic says the scan does not find all congenital conditions, does not diagnose anything and can give false results, though it poses no harmful risks. If something needs a closer look, more tests follow, such as a maternal fetal medicine visit, amniocentesis or a fetal echocardiogram.
Learning the sex is optional. Cleveland Clinic says that in most cases you can learn the sex at the scan, depending on the baby’s position. UPMC says to tell the sonographer before the ultrasound starts if you want it to be a surprise. Planning a reveal? See gender reveal ideas.
Vaccines. The vaccine line reflects UPMC as read in October 2026. Guidance changes, so confirm with your provider.
What to Do This Week: A Simple Checklist
Book or confirm your anatomy scan: the window is around 18 to 22 weeks (Cleveland Clinic).
Keep moving, gently: walking or swimming can spare a sore back or hips (UPMC).
Set up your side sleeping: pillows under your belly or between your legs (MedlinePlus).
Learn the warning signs: see the end of this guide, and save the after-hours number.
Start the fun planning: begin a baby registry checklist, and if you are dreaming of a babymoon, talk your travel plans through with your provider first.
Sleep at 20 Weeks Pregnant
Sleep position. MedlinePlus says side sleeping with your knees bent is likely most comfortable and keeps the baby from putting pressure on the large vein that carries blood back from your legs. Providers often recommend the left side, which also improves blood flow; the right side is fine for a while if your left hip aches; and it is best not to sleep flat on your back. Ask your provider what they recommend.
Build a pillow setup: MedlinePlus suggests pillows under your belly or between your legs, and a rolled blanket at the small of your back. Our guide on how to use a pregnancy pillow walks through the options.
Ease heartburn and bathroom trips: avoid a big meal or lots of fluid near bedtime and limit caffeine (MedlinePlus).
Keep a rhythm: same bedtime and wake time, no exercise right before bed, and a 15 minute warm bath (MedlinePlus).
Night leg cramps: press your feet hard against the wall or stand on the leg (MedlinePlus). You can also ask your provider about treatment.
Sleep aids. MedlinePlus is direct: do not take any sleep aids, including over-the-counter medicines and herbal products, without talking to your provider. See can you take melatonin while pregnant.
For Partners: How to Help at 20 Weeks
Come to the anatomy scan: if you can; plan for around 45 minutes (Cleveland Clinic).
Take on the heavy jobs: laundry baskets, groceries and anything that strains a sore back.
Know the warning signs: read the list below so you can make the call if she is unsure.
Looking Ahead: What Comes Next
Week 22: about 7 1/2 inches crown to rump and about 1 pound, with eyebrows and hair visible (Mayo Clinic). The anatomy scan window closes (Cleveland Clinic).
Week 24: the Office on Women’s Health lists about 12 inches and about 1 1/2 pounds, with fingerprints and footprints formed.
Weeks 24 to 28: glucose screening (UPMC).
Weeks 27 to 28: the second trimester ends (ACOG via UPMC, and Office on Women’s Health).
Call any time something worries you. UPMC names blood clots, preterm birth and preeclampsia as second trimester risks that require emergency care. The CDC says to seek medical care immediately for these urgent warning signs:
A headache that won’t go away or gets worse over time: (CDC), or one with blurred vision, nausea and swelling of the face and hands, which UPMC says could be preeclampsia.
Changes in your vision, dizziness or fainting, or extreme swelling of your hands or face: (CDC).
Vaginal bleeding or fluid leaking: (CDC).
Severe belly pain that doesn’t go away: (CDC). Strong cramps could be preterm labor (UPMC).
Your baby’s movement stopping or slowing: (CDC), once you have been feeling regular movement.
Swelling, redness and warmth in one leg: possible signs of a blood clot (UPMC, CDC).
Trouble breathing, chest pain or a fast-beating heart: (CDC, UPMC).
A fever of 100.4 F or higher, or pain when urinating: (CDC, UPMC).
Severe nausea and throwing up, overwhelming tiredness, or thoughts about harming yourself or your baby: (CDC).
If you cannot reach your provider quickly, go to labor and delivery or the nearest emergency room. For severe trouble breathing, chest pain, heavy bleeding or a seizure, call 911. When you call, say that you are 20 weeks pregnant. This article is general education, not medical advice.
Frequently Asked Questions
How many months is 20 weeks pregnant?
About 4 1/2 months, counting 4 weeks and a few days per month, so you are finishing your 5th month. Months are only a convention, so providers count pregnancy in weeks from your last period, with about 20 weeks to go.
How big is my baby at 20 weeks?
Mayo Clinic lists about 6 1/3 inches (160 millimeters) from crown to rump, which does not include the legs, and about 11 ounces (320 grams). The Office on Women’s Health says about 6 inches and about 9 ounces. Healthy babies vary.
Is it normal not to feel the baby move at 20 weeks pregnant?
It can be. Cleveland Clinic says first movements usually come around 16 to 20 weeks, that in a first pregnancy it is common not to feel movement until 20 weeks, and that an anterior placenta can make movements harder to feel. Some movement is generally felt by 20 to 24 weeks. Talk to your provider if concerned.
What does the 20 week ultrasound check?
Cleveland Clinic says the anatomy scan looks at the fetal heart, brain, spine, kidneys, limbs, face, chest, stomach and intestines, plus the umbilical cord, placenta position and amniotic fluid. It does not find every condition, and more tests follow if something needs a closer look.
Can you find out the sex at 20 weeks?
Usually, if you want to. Cleveland Clinic says that in most cases you can learn the sex at the anatomy scan, depending on the baby’s position. UPMC says to tell the sonographer before the scan starts if you would rather keep it a surprise.
How should I sleep at 20 weeks pregnant?
MedlinePlus says side sleeping with your knees bent is likely most comfortable and keeps pressure off a large vein, that providers often recommend the left side, and that it is best not to sleep flat on your back. Pillows can help. Ask your provider.
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