At 20 weeks you are five months pregnant and exactly halfway through. This is the midpoint of the second trimester, the point at which most women feel physically best, and the week the detailed anatomy scan is most often carried out.
Your baby now weighs around 300 grams and measures roughly 26 centimetres from head to heel. The measurement basis changes at week 14 from crown-to-rump to crown-to-heel, so a jump in the numbers between week 13 and week 14 is a change in how the baby is measured, not a growth spurt.
The short answer: 20 weeks is month 5 and the halfway mark. Baby is about 300 g and 26 cm — banana-sized. The anatomy scan, which checks the heart, brain, spine, kidneys and limbs and locates the placenta, is usually offered between 18 and 22 weeks and most commonly done now. Not feeling movement yet is still normal, especially in a first pregnancy.
Your baby at 20 weeks
The most interesting development this week is in the brain. Distinct areas are being dedicated to each of the senses — smell, taste, hearing, sight and touch — and the nerve pathways connecting them to the body are laying down. Your baby can hear your voice, your heartbeat and the noise of your digestion, and by now responds to loud external sounds.
The skin is still thin but is becoming less translucent as a layer of fat builds beneath it. It is covered in vernix caseosa, a waxy white coating that protects the skin from months of soaking in amniotic fluid, held in place by a fine downy hair called lanugo. Both largely disappear before birth.
Swallowing has become routine. Your baby drinks amniotic fluid, which trains the digestive system, and produces meconium — a dark, sticky first stool that collects in the bowel and is normally not passed until after birth. If you are having a girl, her uterus is now formed and her ovaries already hold their lifetime supply of eggs.
Your body at 20 weeks
The top of your uterus (the fundus) now reaches your navel. From this point, midwives often measure the distance from your pubic bone to the top of the uterus in centimetres — after 24 weeks that measurement roughly matches the number of weeks, which is a quick way of tracking growth between scans.
Your blood volume has risen by around 40% by mid-pregnancy, and that has visible consequences: mild swelling in the feet by evening, a blocked or bleeding nose, and gums that bleed when you brush. All three are normal and all three settle after birth. Your centre of gravity keeps shifting forward, which is where second-trimester back and pelvic pain starts for most women.
Sharp, brief pain low down on one side when you stand up quickly or roll over is usually round ligament pain — the ligaments supporting the uterus stretching. It is harmless. Pain that is constant, rhythmic or accompanied by bleeding is not, and is covered below.
Typical total weight gain by 20 weeks is around 4.5–6.5 kg for a woman who started at a healthy BMI, though the healthy range depends on your starting point. Our weight gain guide sets out the corridor for each BMI band.
The 20-week anatomy scan
Tests and scans around now: The anatomy scan is most commonly done at 20 weeks — every chamber of the heart, the brain, spine, kidneys and limbs are checked, and the placenta is located.
Exact timing varies by country and by your own care plan — your doctor or midwife will confirm the schedule that applies to you.
This scan is the most thorough look at your baby's structure in the whole pregnancy. The sonographer checks the head and brain, the face and lips, the spine along its full length, all four chambers of the heart and the vessels leaving it, the stomach, kidneys and bladder, the abdominal wall, and the four limbs including hands and feet. They also locate the placenta — if it is lying low now, you will usually be offered a repeat scan in the third trimester, and in most cases it has moved up by then.
Most units can tell you the baby's sex at this scan if you want to know and if the position allows. Ask at the start; some will not volunteer it.
✅ Worth doing this week
- Go to the anatomy scan with a full-ish bladder unless told otherwise — it improves the view, and the appointment runs 20–30 minutes
- Keep iron up. Your baby is building an iron store now; lentils, red meat and dark leafy greens, with vitamin C to aid absorption
- Start favouring your side at night. Side sleeping becomes the recommendation later in pregnancy, and the habit is easier to build now — see sleeping positions
- Support your back before it hurts — flat shoes, avoid standing still for long stretches, and consider a pregnancy pillow
- Talk and sing to your bump. Hearing is working, and familiar voices are recognised after birth
When to call your doctor
Call the same day if: you have vaginal bleeding, a gush or steady trickle of fluid, severe or one-sided abdominal pain, regular tightenings, a severe headache with visual disturbance or sudden swelling of the face and hands, pain on passing urine with a fever, or a marked reduction in movements you had previously been feeling every day.
Sudden swelling of the face and hands together with a bad headache and visual changes can signal pre-eclampsia, which is why it warrants a same-day call rather than waiting for the next appointment. Regular tightenings before 37 weeks need assessing for preterm labour.
FAQ — 20 weeks pregnant
How many months is 20 weeks pregnant?
20 weeks is month 5 of pregnancy, and it is the exact halfway point of a 40-week pregnancy. Pregnancy months are not calendar months — they are counted in four- and five-week blocks, which is why 20 weeks lands at the start of month 5 rather than at "five months exactly". Counting runs from the first day of your last period, not from conception.
How big is a baby at 20 weeks?
About 300 g and roughly 26 cm from head to heel — near enough the length of a banana. From this week onwards babies are measured crown to heel; before week 14 the measurement is crown to rump, which is why the number appears to jump between week 13 and week 14. Individual variation is wide and normal, and one measurement below or above average is not a problem on its own.
What does the 20-week anatomy scan check?
The sonographer works through a set list: the brain, face and lips, spine, all four chambers of the heart, the stomach, kidneys and bladder, the abdominal wall, and the arms, legs, hands and feet. They also check where the placenta is lying, measure the amniotic fluid, and confirm growth against your dates. It is a detailed structural check rather than a photo session, which is why it takes 20–30 minutes and the sonographer goes quiet while concentrating.
Should I feel the baby move at 20 weeks?
Many women do, but not feeling movement at 20 weeks is not a cause for alarm. First movements — quickening — are commonly felt anywhere between 16 and 24 weeks, and first-time mothers usually feel them later than women who have been pregnant before. An anterior placenta also cushions the sensation. Formal kick counting does not start until around 28 weeks, once a reliable daily pattern has developed. What matters later is a change from your baby's established pattern, not a fixed number.
Week 20 at a glance
Twenty weeks is month 5 and the halfway point of pregnancy. Your baby weighs about 300 g, measures roughly 26 cm crown to heel, hears your voice and is dedicating separate areas of the brain to each of the senses. Your uterus has reached your navel and your blood volume is up by about 40%, which explains the evening swelling and the bleeding gums. The detailed anatomy scan — the most thorough structural check of the pregnancy — is usually offered between 18 and 22 weeks and most often falls this week. Not feeling movement yet is still within the normal range, particularly in a first pregnancy.
Inside Baby Novum: the ultrasound journal stores each scan's measurements and a photo of the printed report against its date, then plots fetal growth across weeks so you can see the trend rather than one isolated number. The weight tracker plots your own gain against the WHO corridor for your pre-pregnancy BMI, and everything stays on your phone.