20 Week Scan
Twenty weeks is NHS anomaly-scan territory: the most clinically detailed look most babies get during pregnancy. Here's what the NHS appointment screens for, how a private mid-pregnancy scan in Gosforth sits alongside it, and what we see on screen at the halfway mark.
Quick Answer
The NHS schedules its 20 week anomaly scan at this gestation, a specialised screening appointment that checks for 11 specific fetal conditions and is the diagnostic gold standard at this stage. Your baby is around 25cm long and roughly 300 grams, with every major organ formed. Most mums have felt definite movement by now. A private 20-week scan in Gosforth sits alongside (rather than instead of) the NHS appointment, with longer time, family-friendly seating, gender confirmation if you'd like it, photos and a relaxed setting. At our clinic a 20-week well-being scan is £65, or a Luxury Gender Reveal is £95.
What's Happening at 20 Weeks
Twenty weeks is the pregnancy halfway mark and a remarkable point of completeness. Your baby is roughly banana-sized, around 25 centimetres head-to-heel, weighing in at about 300 grams. Every major organ has formed; the work now is refining function rather than building new structure. The kidneys turn out around 7ml of urine an hour. The brain has all the neurons it will ever have, and those neurons are wiring themselves to each other at extraordinary pace. The pancreas has started producing insulin, the gallbladder is producing bile, and the digestive system is rehearsing by swallowing amniotic fluid.
Outwardly baby looks like a small, finished person. The skin has thickened from the translucent paper of earlier weeks and is now coated in vernix, the creamy white layer that protects baby's skin from the amniotic fluid right through to birth. Eyebrows and eyelashes are fully there. Fingernails have grown to the tips. The genitalia are unmistakable on ultrasound, which is part of why gender is so reliably identifiable at this point, whether on a standalone gender determination scan or as part of a celebratory luxury gender reveal package. If you're carrying a girl, her ovaries already hold millions of egg cells (a number that, paradoxically, will fall as she grows). If a boy, the testes have begun their slow descent from the abdomen, although they won't reach the scrotum until close to birth.
By twenty weeks most mums, even first-timers, can feel definite movement. Those early flutters at 17 or 18 weeks have firmed up into proper kicks and rolls. Baby is settling into sleep-wake cycles of around 20 to 40 minutes and starting to react to outside sounds. This is the gestation at which talking, singing or playing music to your bump genuinely registers on the other side.
The NHS Anomaly Scan: What It Checks
The NHS 20-week scan formally sits inside the Fetal Anomaly Screening Programme (FASP) and is designed to screen for 11 specific conditions. It runs 30–45 minutes, is delivered by sonographers with dedicated anomaly-screening training, and is the most thorough single look at fetal anatomy your baby will get across the pregnancy. There's no ambiguity: clinically, it's the gold standard at this stage.
The conditions on the screen list are anencephaly, open spina bifida, cleft lip, diaphragmatic hernia, gastroschisis, exomphalos, serious cardiac abnormalities, bilateral renal agenesis, lethal skeletal dysplasia, Edwards' syndrome (trisomy 18) and Patau syndrome (trisomy 13). Beyond that, the scan confirms placenta location (which matters for planning birth, a low-lying placenta may need follow-up monitoring), checks amniotic fluid volume, measures growth against the expected ranges, and reviews the umbilical cord.
If everything looks normal, the NHS sonographer will tell you so during the appointment. If something is flagged, you'll be referred to a fetal medicine specialist for further investigation, usually within one to three weeks. Whatever else you book privately, please don't skip the NHS appointment. Our NHS vs private comparison sets out the full case. It's the single most clinically important scan of the pregnancy.
Scan Packages for Week 20
Wellbeing & Reassurance Scan
From 15 weeks
A 15-minute reassurance check between NHS appointments. Heartbeat, position, growth, photos and digital images.
View package →Luxury Gender Reveal
From 15 weeks
If your NHS trust didn't disclose gender, a celebratory reveal package with confetti, sealed envelope option, gender card, photos and digital images.
View package →Book Your 20 Week Private Scan
Same-day or next-day slots often available at our Gosforth clinic. CQC-regulated, experienced and registered sonographers, two years on Bakers Yard, a fast-growing wall of five-star Google reviews since 2025.
The NHS Anomaly Scan vs a Private 20 Week Scan
The 20-week anomaly scan is the most detailed look at baby's anatomy the NHS performs, and nothing private replaces it. What a private scan adds at this stage is time, guests and something to take home.
| Aspect | NHS | Numi Scan Gosforth |
|---|---|---|
| Available at 20 weeks | Yes, the anomaly scan | ✓Yes, a Wellbeing Scan or a 4D peek |
| Main purpose | Detailed structural survey of baby's anatomy, placenta position and fluid | ✓Reassurance, bonding and keepsake images |
| Finding out the sex | Policy varies by trust, and some will not tell you | ✓Told on the day or sealed in an envelope, your call |
| Appointment length | 20–30 minutes, clinical in tone | ✓15–30 minutes depending on package |
| Guests | Usually one partner | ✓Mum plus up to 9 guests |
| Images to take home | Sometimes, often for a small charge | ✓Prints and every digital image by email |
| Cost | Free | ✓From £65 |
Never skip the NHS anomaly scan. It is a diagnostic examination; ours is a reassurance scan and is not designed to replace it.
Frequently Asked Questions
Most of the parents we see at this gestation treat the private scan as an addition rather than a substitute. The NHS 20-week anomaly scan is the diagnostic gold standard at this stage, delivered by sonographers with specialist anomaly-screening training, and we'll always advise you to keep that appointment. A private 20-week scan at our Gosforth clinic offers something different on top: longer time, family-friendly seating, photos and digital files included as standard, and an atmosphere geared towards enjoying the moment rather than ticking screening boxes.
The NHS 20-week scan sits inside the Fetal Anomaly Screening Programme and screens for 11 specific conditions: anencephaly, open spina bifida, cleft lip, diaphragmatic hernia, gastroschisis, exomphalos, serious cardiac abnormalities, bilateral renal agenesis, lethal skeletal dysplasia, Edwards' syndrome and Patau syndrome. It also confirms placenta location, checks amniotic fluid volume and reviews fetal growth. It's careful, structured clinical work and stands as the diagnostic gold standard at this gestation.
As a rule, no, and we don't market our scans that way. The NHS appointment is delivered by sonographers with specialist anomaly-screening training and is more comprehensive for that purpose than a standard private reassurance scan. Our 20-week appointment is focused on bonding, gender confirmation if it hasn't already been done, and a comfortable family experience. If you have specific anomaly concerns we can talk through which detailed scan would suit, but for most families the NHS scan handles the screening and the private scan handles everything else.
Yes, at twenty weeks gender is essentially unmistakable on ultrasound (provided baby cooperates) and we can confirm to 99%+ accuracy. If you'd like to find out at the private appointment, we can fold that into the scan. NHS gender disclosure varies trust by trust these days, some no longer share at the anomaly scan due to staffing pressures, others still do, so a private scan is a dependable way to know either way.
If our experienced and registered sonographer spots something that warrants further investigation, we'll explain what we're seeing clearly on the day, write it into a detailed report, and tell you exactly what happens next. That usually means sharing the report with your midwife or GP and letting the NHS pathway pick up the formal follow-up. We don't make alarming statements without imagery to back them, and nobody is sent home to interpret findings on their own.
Our well-being scan at £65 is the most-booked option for a 20-week reassurance check: a 15-minute appointment covering heartbeat, position and growth, plus printed and digital images. If you'd also like a gender reveal moment (because your NHS trust didn't disclose, or you want something celebratory anyway) the Luxury Gender Reveal at £95 adds confetti, the sealed envelope option and a gender card. All photos and digital images are included on both.
Almost always, twenty-week babies are busy. By this stage most mums have already felt those first flutters, and on ultrasound you'll usually see kicks, stretches, hand movements, occasionally hiccups. Babies wriggle, sleep, sometimes hide their faces. It happens. If yours has decided on a nap when you arrive, a short walk around the clinic or a sip of cold water usually does the trick, and we always book in enough time to wait for a co-operative position.