Pregnancy Week 20: Baby Size & Practice

At 20 weeks

At 20 weeks pregnant you are halfway there, and your baby is about the size of a banana (kela), around 25.6 cm from head to heel (NHS) and about 330 g at the WHO median. Your baby is coated in vernix, may be sucking a thumb, and can hear sounds from outside your uterus. The top of your womb is now usually level with your belly button.

Your Baby at 20 Weeks

From this week the NHS measures babies from head to heel rather than head to bottom, which is why the length jumps compared with week 19. Your baby is covered in a white, greasy layer of vernix, thought to stop the skin drying out in the amniotic fluid, and is getting more active each day, kicking, punching, turning and perhaps sucking a thumb.

Fingerprints have formed, permanent teeth sit in the gums beneath the baby teeth, and cartilage is turning into bone as the bone marrow starts making blood cells. The ears haven't finished developing, but your baby can hear sounds from outside your uterus, and stores of brown fat are building up to keep them warm after birth (Pregnancy, Birth and Baby). The WHO Fetal Growth Charts give a median estimated weight of about 330 g; healthy babies vary widely, and your scan report is what matters.

Your Body This Week

The top of your uterus, called the fundus, is usually level with your belly button now, and your belly measurement in centimetres should roughly match your weeks of pregnancy, about 20 cm at 20 weeks (Pregnancy, Birth and Baby). With less room for your heart and lungs, you may feel breathless, especially lying on your back, so try lying on your side with a pillow for support.

Sudden, sharp calf pains that wake you at night are probably cramp; the NHS suggests rubbing the muscle hard or pulling your toes up towards your ankle, and exercising more in the day may help. Round ligament pain, an ache or sharp stab at the sides of your bump as the uterus stretches, is also common.

When to call your midwife or doctor: If you are worried about any pain in your abdomen, talk to your doctor or midwife, because other complications can cause feelings similar to round ligament pain (Pregnancy, Birth and Baby). Seek medical advice for any bleeding (NHS).

Garbh Sanskar This Week

A small daily practice for this stage, from Mamta’s 1:1 sessions. It is tradition and gentle self-care, not medical advice, so keep every check-up and follow your doctor or midwife first.

Mantra: The Garbha Raksha Stotram is a devotional prayer of uncertain authorship that asks Brahma, as Prajapati, to protect the pregnant woman and her child. Read or chant one verse softly each day if it speaks to you; a monthly schedule or 108 repetitions is one tradition, not a requirement (Garbh Sanskar mantras).
Music: Your baby's ears can now pick up sounds from outside the uterus, and from around this fifth month babies begin to respond to sound. Share a bhajan or calm song you love at a comfortable volume, as a moment of closeness rather than a lesson.
Gentle movement: Mamta's practice this week is side-lying rest: lie on your left or right side with a pillow between your knees and another under your bump, and breathe slowly with a long, unforced out-breath. Avoid lying flat on your back for long, and practise only with your doctor's or midwife's clearance.
Food: Traditionally, Charaka's fifth month continues with ghee made from milk butter, and a little on warm rice or dal is enough. Take it alongside the iron, calcium and folic acid your doctor recommends.
Garbh samvad (a line to say to your baby): We're halfway, little one. Thank you for growing with me.

Check-ups Around This Week, Wherever You Live

At 20 weeks the detailed anomaly (morphology) scan is the main check-up in every country, though the timing windows differ slightly.

Where you live	What is usually offered
India	Your doctor will usually advise an anomaly scan around 18 to 20 weeks, and your second of at least four antenatal visits falls between 14 and 26 weeks. Under the PCPNDT Act, no one may tell you or your family the baby's sex, by words, signs or any other manner.
UK	The NHS 20-week screening scan is offered between 18 and 21 weeks. The whooping cough vaccine is usually offered around 20 weeks, and you can have it from 16 up to 32 weeks.
USA	The anatomy ultrasound is usually done between 18 and 22 weeks, with visits traditionally every 4 weeks until 28 weeks.
Australia	The morphology scan is done between 18 and 22 weeks, and the whooping cough (pertussis) vaccine is recommended in every pregnancy, ideally between 20 and 32 weeks.

Schedules change and differ between hospitals, so your own care team’s plan always comes first.

Questions About Week 20

Can my baby hear me at 20 weeks?

Yes, to a degree. Pregnancy, Birth and Baby says your baby's ears are still developing but can already pick up sounds from outside your uterus, and a study of babies' responses found a first reaction to sound at around 19 weeks. Talking or singing to your bump is a gentle way to feel close.

Will the anomaly scan tell me my baby's sex in India?

No. Under the PCPNDT Act, no one in India may tell you or your relatives the sex of your baby, by words, signs or any other manner. The scan is there to check your baby's development and your placenta.

What does fundal height mean at 20 weeks?

The fundus is the top of your uterus, and at 20 weeks it is usually level with your belly button. Your doctor or midwife measures your belly at each check-up, and Pregnancy, Birth and Baby says the measurement in centimetres should be about the same as your weeks of pregnancy, roughly 20 cm now.

Practise With Mamta, Wherever You Are

Mamta guides expecting mothers through private 1:1 Garbh Sanskar sessions online, scheduled in your own time zone, from the first trimester to the last week. Start with a free conversation on WhatsApp or read how sessions work.

Sources

Mamta is not a doctor. Medical points on this page come from the sources below, checked in October 2026. Sizes are approximate and babies vary; your scan report is what matters.