Creator: Dr. Devang Patel
Published: 2026-09-07

The anomaly scan - also called the level 2 scan, the TIFFA scan or the mid-pregnancy scan - is a detailed ultrasound done between 18 and 22 weeks. By this stage the baby’s organs have formed and are large enough to be examined one by one. For most parents it is a reassuring scan. For a small number, it picks up a finding that changes how the rest of the pregnancy, the birth and the newborn care are planned.

Why 18 to 22 weeks?

Before 18 weeks, some structures, especially the heart and the face, are too small to assess in detail. After 22 to 23 weeks the bones are more calcified and shadow the organs, and the baby has less room to move into useful positions. There is also a practical reason: if a serious condition is found, parents need time to have further tests, meet specialists and make informed decisions within the time limits set by Indian law. Booking the scan close to 19 to 20 weeks leaves room for a repeat if the view is not complete.

The anomaly scan is recommended for every pregnant woman, not only those considered high-risk. Most babies with a structural condition are born to parents with no family history and no risk factors, which is why the scan is part of routine antenatal care in FOGSI and WHO guidance.

What is checked

The scan follows a systematic checklist based on international standards (ISUOG and the Fetal Medicine Foundation). The sonologist looks at:

Head and brain: skull shape, the fluid spaces (ventricles), the cerebellum and the midline structures
Face: the lips for cleft lip, the profile, and the eye sockets
Spine: each vertebra along its length, and the skin covering it, for spina bifida
Heart: the four chambers, the valves, and the outflow vessels - the part of the scan that takes the most time
Chest and diaphragm: the lungs and the muscle separating chest from abdomen
Abdomen: the stomach, the abdominal wall, the kidneys and the bladder
Limbs: arms, legs, hands and feet, and the long bones
Growth measurements: head, abdomen and thigh bone, to compare with the expected size for the dates
Placenta position, the amount of amniotic fluid, and the umbilical cord vessels

Many centres also measure the length of the cervix at this scan, usually with a short internal scan, because a short cervix identifies women at higher risk of preterm birth who may benefit from treatment.

Pre-natal sex determination is prohibited under the PCPNDT Act. The sex of the baby is not detected or disclosed at any scan.

How to prepare

Bring your earlier scan reports, especially the dating scan and the NT scan, and your blood test results
A full bladder is usually not needed; you may be asked to empty it before the cervix check
Wear loose, two-piece clothing
Plan for 30 to 60 minutes. If the baby is lying in an awkward position, you may be asked to walk, change position, or return another day
Eat normally beforehand; there is no need to fast or drink sugary drinks
One family member can usually be present

What the scan can and cannot tell you

A detailed anomaly scan detects a large proportion of major structural problems, such as spina bifida, anencephaly, major heart defects, and abdominal wall defects. It cannot detect everything. Some heart conditions, minor abnormalities, and problems that develop later in pregnancy may not be visible at 20 weeks. The view also depends on the mother’s body habitus, the baby’s position and the amount of fluid.

An anomaly scan is not a genetic test. A normal scan lowers, but does not remove, the chance of a chromosomal condition. If you have not had screening for Down syndrome, ask about it.

Soft markers and findings

Sometimes the report mentions a “soft marker” - a finding such as a bright spot in the heart, slightly prominent kidney pelvis, or a mild variation in a fluid space. On their own, most soft markers are seen in healthy babies and are not abnormalities. Their meaning depends on your earlier screening results, and they are interpreted together rather than in isolation.

If a structural finding is seen, the next steps may include:

A repeat or more detailed scan by a fetal medicine specialist
A fetal echocardiogram to look at the heart in detail
Genetic testing through amniocentesis, and counselling about what the results mean
Discussion with a paediatric surgeon or cardiologist about treatment after birth
Planning the place and timing of delivery so the newborn team is ready

Decisions are always made with you, after enough time and information. Under the Medical Termination of Pregnancy (Amendment) Act, 2021, a pregnancy with a substantial fetal abnormality may be considered for termination beyond 24 weeks only through a medical board, which is one more reason to keep the scan within the recommended window.

After a normal scan

You will receive a written report that lists each structure examined, the measurements, the estimated weight and the placental position. Keep it with your antenatal file and bring it to every visit and to the labour ward. If any part of the anatomy could not be seen clearly, the report will say so, and a short repeat scan is arranged.

Most anomaly scans are normal. Your care then continues with routine antenatal visits, a glucose test at 24 to 28 weeks, and, depending on your history, growth scans in the third trimester. If the placenta was low-lying, a repeat scan around 32 weeks checks whether it has moved up.

When to see a doctor

Book your anomaly scan as soon as your dating scan confirms your due date, so you have a slot between 18 and 22 weeks. Contact the clinic if you have bleeding, leaking fluid, abdominal pain or contractions at any time. At Divine Women’s Hospital, Gota, Dr. Devang Patel - a fetal medicine specialist with Fetal Medicine Foundation (UK) accreditation for the NT scan - performs level 2 scans and explains the findings with you during the same visit.

More patient guides

This guide is general information for patients and does not replace a consultation with your own doctor.

The anomaly scan at 18–22 weeks: what it checks and what to expect