When is the best time to have an anomaly scan?

The anomaly scan is most informative between 18 and 22 weeks of pregnancy. At this stage, your baby is large enough for detailed anatomical assessment but still has sufficient amniotic fluid around them for clear views. We can perform the scan from 18 weeks.

Can the anomaly scan detect Down's syndrome?

The anomaly scan is a structural survey and is not designed to screen for chromosomal conditions such as Down's syndrome. If you wish to screen for chromosomal abnormalities, we recommend a combined first trimester screening test (11-14 weeks) or non-invasive prenatal testing (NIPT).

What happens if something is found?

If a potential abnormality is identified, your sonographer will explain the finding clearly and calmly. The written report will include the finding and recommended next steps, which may include a referral to a fetal medicine specialist. The vast majority of findings turn out to be minor variants or resolve on follow-up.

Will I find out the baby's sex?

We can attempt to determine the sex of your baby during the anomaly scan if you wish. Please let us know at the start of the appointment. Note that sex determination is not always possible depending on the baby's position.

Is the scan safe for my baby?

Yes. Diagnostic ultrasound has been used safely in pregnancy for over 50 years. It uses sound waves rather than radiation and is considered safe at the power levels used in diagnostic imaging.

How long does the scan take?

The anomaly scan appointment is 30-45 minutes. This extended time allows a thorough systematic assessment of all anatomical structures without rushing.

HCPC Registered— All sonographers

CQC Compliant— Regulated clinic

Same-Day Available— Mon – Sat

Written Report— Within 24 hours

HCPC Registered

CQC Compliant

Same-Day Available

Written Report

Pregnancy Scans

Anomaly Scan (20-Week Scan)

A detailed mid-pregnancy structural survey examining your baby's anatomy from head to toe, checking for over 70 physical conditions and confirming healthy development.

30-45 minutes

Same-day appointments

Marylebone, London W1

HCPC RegisteredCQC CompliantSame-Day AvailableWritten Report IncludedPregnancy Specialist

£235

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4.9/5 from 600+ patients

HCPC-registered sonographers

Written report within 24 hours

Same-day appointments available

CQC-compliant clinic

Understanding Your Situation

The Scan That Checks Your Baby From Head to Toe

The 20-week anomaly scan is one of the most significant milestones of pregnancy -- a detailed structural survey that examines your baby's brain, heart, spine, limbs, and organs to check that everything is developing as expected. While the vast majority of scans show a healthy baby, having this thorough assessment provides genuine reassurance and, where needed, allows time to plan appropriate care. Our specialist sonographers take the time to explain every finding clearly and answer all your questions. Based at 29 Weymouth Street in Marylebone, Central London, we provide same-day appointments with written reports included.

Clinical Overview

What is an Anomaly Scan?

The anomaly scan, also known as the mid-pregnancy or 20-week scan, is a detailed ultrasound examination typically performed between 18 and 22 weeks of pregnancy. It systematically surveys your baby's anatomy to check for structural abnormalities. The NHS offers this scan routinely, but private anomaly scans at specialist clinics offer longer appointment times, superior equipment, and immediate written reports. Approximately 1 in 50 babies has a structural abnormality detectable by ultrasound, making this scan a vital part of antenatal care.

Is This Scan Right for You?

Who Should Book This Scan?

All pregnant women between 18 and 22 weeks of pregnancy

Women who want a more detailed assessment than the standard NHS scan allows

Patients who were unable to attend their NHS anomaly scan appointment

Women with a family history of congenital conditions seeking reassurance

Those who want extended time with a specialist sonographer to ask questions

Women carrying twins or multiples requiring detailed individual assessments

Diagnostic Scope

What This Scan Can Detect

Brain and Skull

Assessment of cerebral ventricles, cerebellum, and skull shape to detect conditions such as hydrocephalus or neural tube defects.

Heart Structure

Four-chamber view and outflow tracts to identify congenital heart defects, which affect approximately 8 in 1,000 births.

Spine

Longitudinal and transverse views to check for spina bifida and other neural tube defects.

Abdominal Wall

Assessment for gastroschisis and exomphalos, where abdominal organs develop outside the body wall.

Limbs and Skeleton

Measurement and assessment of all four limbs, hands, and feet for skeletal dysplasias.

Placenta and Fluid

Placental location, umbilical cord insertion, and amniotic fluid volume assessment.

Facial Structures

Assessment of lip, palate, and facial profile where possible.

Your Appointment

What Happens During Your Scan

Arrival and welcome

Arrive with a comfortably full bladder. Our team will greet you and take you through to the scanning room.

Systematic anatomy survey

The sonographer methodically examines each anatomical structure in a standardised sequence, spending adequate time on each area.

Heart and spine assessment

Extra time is dedicated to the heart and spine -- the two most complex structures assessed during this scan.

Measurements and growth

Head circumference, abdominal circumference, and femur length are measured to confirm appropriate growth for gestational age.

Report and images

A written report with scan images is provided before you leave, with all findings explained clearly.

Before Your Appointment

How to Prepare for Your Scan

1
Arrive with a moderately full bladder -- drink 2-3 glasses of water one hour before and do not empty your bladder
2
Wear loose, comfortable clothing that allows easy access to your abdomen
3
Eat normally before the scan -- there is no need to fast
4
Bring your maternity notes if you have them
5
Allow 45-60 minutes for your appointment including discussion time

After Your Scan

Understanding Your Anomaly Scan Results

The majority of anomaly scans show a structurally normal baby, providing enormous reassurance. Your sonographer will explain all findings during the scan and provide a written report before you leave. If a potential abnormality is identified, the report will describe the finding clearly and recommend appropriate next steps, which may include a referral to a fetal medicine specialist or further imaging. Our team will support you through any findings with sensitivity and clarity.

Why Private?