At 20 weeks pregnant, your baby is about the size of a banana — roughly 25 to 26 cm head to heel (about 10 inches) and around 300 g, a little over 10 ounces. This is the halfway point of pregnancy, and your baby's skin is now covered in vernix, the waxy coating that protects it in the amniotic fluid.
Week 20 is the middle of the story: about 20 weeks behind you, roughly 20 ahead. It is also when most people have the detailed mid-pregnancy scan, so it lands as a double milestone.
Averages, not targets
Every number here is an average with a wide healthy range around it, and plenty of people at 20 weeks feel almost nothing on this list. This is general information, not medical advice; your own doctor, midwife or national antenatal programme always comes first.
How big is your baby at 20 weeks pregnant?
About the size of a banana — the comparison nearly every pregnancy app and magazine reaches for this week. A large mango or a good-sized carrot works just as well. In numbers, roughly 25 to 26 cm and around 300 g: about 10 inches and a little over 10 ounces.
Both figures are approximations: scan measurements carry a margin of error, and two entirely healthy babies at exactly 20 weeks can differ noticeably. Growth is judged by the pattern over time, not one number on one day.
Why your baby suddenly looks much longer this week
Up to about week 14, babies are measured crown to rump — head to bottom — because the legs stay curled up. From around week 20 the measurement switches to crown to heel, head to toe. Week 20 is exactly where that changeover happens, which is why one chart shows around 16 cm and another around 25 cm for nearly the same stage. The baby did not double overnight; the ruler changed.
How many months is 20 weeks pregnant?
Pregnancy is counted in gestational weeks, from the first day of your last menstrual period (LMP) rather than the day you conceived. Conception usually happens about two weeks later, so at 20 weeks pregnant your baby has been developing for roughly 18 weeks — a quirk of the counting, not a problem with your dates.
In months, week 20 falls in the fifth month — most people just say "five months" — halfway through the second trimester and halfway to 40 weeks, give or take. To see how this week connects to the ones either side of it, our pregnancy week-by-week guide follows the whole journey from the first positive test to birth.
What your baby is doing at 20 weeks
- Vernix caseosa covers the skin. A waxy, cheesy-looking coating protects the skin from months of soaking in fluid, and later eases the journey through the birth canal; some babies are still visibly covered at delivery.
- Swallowing, and the first meconium. Your baby swallows more fluid now, giving the digestive system practice. What cannot be used collects in the bowel as meconium — the dark, sticky first nappy you will meet after birth.
- Taste buds are forming. Flavours from what you eat pass into the amniotic fluid, giving your baby an early taste of your cooking.
- Hearing is sharpening. Your voice and heartbeat are the daily soundtrack, and around this stage many babies startle or shift at a sudden loud noise — a slammed door, a barking dog, the vacuum.
- Sleep and wake cycles appear. Your baby now has recognisable stretches of rest and activity, and they almost certainly will not match yours — being nudged awake the moment you lie down is a familiar complaint from now on.
What you may be feeling at 20 weeks
The top of the uterus now reaches roughly the level of your navel. Most people feel movement clearly by week 20, first-time mothers included — though a placenta lying at the front of the uterus can muffle those kicks for a few more weeks.
Common around 20 weeks:
- Heartburn and reflux. Hormones relax the valve at the top of the stomach while the uterus presses upward. Smaller, more frequent meals and staying upright after eating often help. Check with your doctor, midwife or pharmacist before taking anything for it, herbal remedies included.
- Backache. Your centre of gravity is shifting and your ligaments are looser than usual; flat shoes and gentle movement help more than rest alone.
- Leg cramps, often at night. Common in the second half of pregnancy, and usually harmless, if unwelcome at 3am.
- Swollen ankles and feet. Mild swelling that builds through the day and settles overnight is expected. Sudden swelling, or swelling of the face and hands, is not — see the list below.
- Stretch marks. Pink, red, purple or brown lines may appear on the bump, breasts, hips or thighs. Whether you get them is mostly genetics, and they fade to pale silvery lines with time.
- Breathlessness. Being out of puff on the stairs is common as the uterus rises. Sudden breathlessness, chest pain or a pounding heart is different, and needs urgent attention.
- More vaginal discharge. Thin, milky and mild-smelling is normal. Itching, burning, a strong smell or a change in colour is worth checking.
- A healthy appetite. Nausea has usually gone and hunger is often back with force. There is no need to eat for two — eating regularly and reasonably well is plenty.
One thing you do not need to do this week is formally count kicks; structured counting begins much later, once a recognisable pattern exists. What matters now is simpler: once you are feeling movement regularly, any reduction or change is worth phoning your maternity unit about immediately, at any hour, however often you have called before.
What to do this week: the 20-week anomaly scan
The mid-pregnancy scan — the anomaly scan, the anatomy scan, or simply "the 20-week scan" — is usually offered between 18 and 22 weeks, and week 20 is the most common slot. The sonographer checks:
- the brain and skull shape, the face and the spine;
- the heart, its chambers and the major vessels leaving it;
- the stomach, kidneys, bladder and abdominal wall;
- the arms, legs, hands, feet and bone development;
- where the placenta is sitting, and how much amniotic fluid there is;
- your baby's growth measurements, checked against your dates.
Finding out the sex is a side note, not the purpose — and clinic policy or national rules may mean it is not shared at all. The room can go quiet: long silences usually mean the sonographer is concentrating on a tricky view, not withholding news. Being asked to walk about or come back another day is common, and normally just means your baby was lying awkwardly.
From around this stage, most guidance also suggests settling to sleep on your side rather than flat on your back, because the growing uterus can press on a major vein; if you wake up on your back, simply roll over. And antenatal schedules genuinely differ between countries and clinics, so follow your own doctor, midwife and national programme rather than any timeline you read online, this page included.
Halfway there — follow every week from here
Babymind tracks your pregnancy week by week with size comparisons and what to expect, then carries on after birth with growth and development tracking, sleep tracking, the AI cry analyser, a food-safety reference, baby names and a parent community — in 11 languages.
Get the Babymind appCall your doctor or midwife now if you have
Most of what week 20 brings is ordinary. These are not, and none of them is ever a bother:
- Vaginal bleeding, however light.
- Severe or persistent abdominal pain, or cramping that keeps returning.
- Fluid leaking from the vagina, whether a trickle or a gush.
- Fever, chills, or feeling generally unwell.
- A severe headache with visual changes such as flashing lights or blurring, or sudden swelling of the face, hands or feet.
- Pain or burning when you pass urine, or blood in your urine.
- Reduced or changed movement, once you are feeling your baby regularly.
- Any sudden, severe symptom that frightens you, including painful swelling or redness in one leg.
Halfway is an emotional place to stand. Some people reach week 20 excited; others arrive carrying anxiety from a previous loss, or doing this alone. Nobody can promise how a pregnancy will unfold — but you are allowed to ask questions, ask them twice, and call your care team whenever something feels wrong.
