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Second trimester

20 weeks pregnant

Your baby is about the size of a banana

Week 20 of 40 · Second trimester About 20 weeks to your due date
  1. 1st trimester weeks 1–12
  2. 2nd trimester weeks 13–26
  3. 3rd trimester weeks 27–40+
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By Clever Mum Parenting · Parenting guides

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How big is the baby at 20 weeks pregnant?

At 20 weeks pregnant, your baby is about the size of a banana, roughly 25.6cm and around 300g. You're halfway there. From now, length is measured head-to-heel. The baby is swallowing amniotic fluid and producing meconium (first poo). They have regular sleep-wake cycles. These are typical averages — your midwife's measurements are the ones that matter for your pregnancy.

What might you feel at 20 weeks?

Most people at 20 weeks notice some mix of the symptoms below — and plenty notice none of them. Most people have a clear bump by now and many feel regular movements. This is often when the anomaly scan happens. You might feel more energetic and comfortable. None of this is a diagnosis; contact your midwife if something worries you.

Common symptoms this week

  • Clear, established bump
  • Regular noticeable movements
  • Feeling more comfortable than either end of pregnancy

Symptom lists are typical, never exhaustive — and having none of them is normal too.

What should you do at 20 weeks pregnant?

The useful job this week is practical, not medical. After the 20-week scan is a good time to start researching big purchases — pushchair, car seat and cot have the longest lead times. Pair it with the NHS week-by-week guide if you want a second description of the same stage.

Week 20 checklist

  • Attend the anomaly scan — a detailed development check of heart, brain, spine, limbs and placenta position
  • Ask for your MATB1 certificate from around now — it unlocks maternity pay
  • Start researching the big purchases (pushchair, car seat, cot)

What antenatal care is due around 20 weeks?

These appointments, vaccines and deadlines fall around this stage. Your maternity team will confirm your own dates.

  • Quadruple test if you missed combined screening. If you are past 14 weeks, the NHS may offer the quadruple blood test between 14 and 20 weeks. It checks for Down's syndrome but is not as accurate as the combined test. NHS: screening in pregnancy
  • Whooping cough vaccine (from 16 weeks). Offered in every pregnancy from 16 weeks, usually around 20 weeks. Antibodies pass to your baby before they can have their own vaccines at 8 weeks. Pregnancy and baby vaccines
  • 20-week scan (usually 18 to 21 weeks). The mid-pregnancy scan screens for 11 physical conditions and takes around 30 minutes. It cannot find every condition, and it is your choice whether to have it. What the 20-week scan checks
  • Tell your employer at least 15 weeks before your due date. GOV.UK says to tell your employer when the baby is due and when you want your leave to start at least 15 weeks before your due date — around 25 weeks pregnant. For Statutory Maternity Pay you also need proof of pregnancy, usually the MATB1 your midwife or GP can give you from 20 weeks before the due date. Estimate your 2026/27 maternity pay

What else is useful at 20 weeks?

Use the week page for size and symptoms; use the guides below for the decisions that actually sit in this window — pay, packing, car seats, labour signs.

20 weeks pregnant: common questions

What does the 20-week anomaly scan check?

A detailed structural check of the baby — brain, face, spine, heart, stomach, kidneys, limbs — plus the placenta's position and amniotic fluid. Most scans are reassuring; if anything needs a closer look you'll be referred to a specialist, usually within days.

How big is my baby at 20 weeks pregnant?

At 20 weeks, your baby is approximately the size of a banana, about 25.6cm and around 300g. These are approximate averages — every baby grows at its own pace.

What's happening at 20 weeks pregnant?

You're halfway there. From now, length is measured head-to-heel. The baby is swallowing amniotic fluid and producing meconium (first poo). They have regular sleep-wake cycles. For you: most people have a clear bump by now and many feel regular movements. this is often when the anomaly scan happens. you might feel more energetic and comfortable.

What appointments or vaccines are due at 20 weeks pregnant?

Around 20 weeks: quadruple test if you missed combined screening; whooping cough vaccine; 20-week scan; tell your employer at least 15 weeks before your due date. Your maternity team will confirm the dates that apply to you.

Which trimester is 20 weeks?

20 weeks pregnant is in the second trimester. The first trimester runs to the end of week 12, the second from weeks 13 to 26, and the third from week 27 to birth.

Sources & further reading

This is general information, not medical advice — every pregnancy is different. For anything that worries you, and for all your antenatal care, speak to your midwife or GP. If your baby's movements ever slow down or change, contact your maternity unit immediately, day or night.