Every pregnancy involves scans. Not every pregnancy involves the same ones. And almost nobody explains in advance which are routine, which are optional, and what each one is looking for.
This is the list of scans during pregnancy as it applies to most women. It is laid out by month, with what each scan checks, why it is timed the way it is, and what "an extra scan" usually means. It is written by a doctor who is both a gynaecologist and a radiologist — the person describing these scans is the one who performs and reads them.
If you are at the very beginning, your first pregnancy checkup covers the initial visit. Our gynaecology department in Sonipat does all of the scans below in-house.
One thing before the list
Sex determination is illegal in India. No scan here will tell you the sex of your baby, and no sonographer will answer the question. Our obstetric ultrasound is PC-PNDT compliant, and staff are legally obliged to refuse. Please do not ask — it puts them in a difficult position, and the law exists for a good reason.
With that said, here is what the scans do tell you.
Months 1–3: the first trimester
The dating scan — 6 to 9 weeks
Usually your first scan, often done with a vaginal probe because the picture is far clearer this early. It is not painful.
It checks three things: that the pregnancy is inside the uterus and not in a tube, that there is a heartbeat, and how many babies there are. It also measures the embryo to date the pregnancy. That is far more accurate than counting from your last period, and the date becomes the reference for everything that follows.
If you have bleeding or pain before this scan, it may be brought forward.
The NT scan — 11 to 14 weeks
The nuchal translucency scan measures a small fluid space at the back of the baby's neck, alongside a blood test called the dual marker. Together they estimate the chance of certain chromosomal conditions such as Down's syndrome.
Two things to understand about this scan. First, it is a screening test, not a diagnosis — it gives a probability, not a yes or no. Second, its timing window is narrow: after fourteen weeks the measurement is no longer reliable, which is why your doctor will be specific about the date.
Many women also have a general early anatomy check at this scan.
Months 4–6: the second trimester
The anomaly scan — 18 to 22 weeks
Sometimes called the level 2 scan or the TIFFA scan. This is the most detailed scan of the pregnancy and the one most women remember.
It examines the baby's structure in detail: brain, spine, heart, kidneys, limbs, abdomen, face. It also checks where the placenta sits and how much fluid surrounds the baby. It takes longer than the others, often twenty to forty minutes. It may need repeating if the baby is not cooperating.
Most anomaly scans are entirely normal. Where something is found, it is usually minor and simply monitored. The scan exists so that anything significant is known early, when there is time to plan.
The quadruple marker — 15 to 20 weeks
Not a scan but a blood test, done in this window if the first-trimester screening was missed or as an addition to it. It is part of the pregnancy profile test list rather than the scan schedule, but it belongs alongside the anomaly scan because the two are often discussed together.
The NHS guide to ultrasound scans in pregnancy describes this scan sequence in similar terms if you want a second reference.
Months 7–9: the third trimester
The growth scan — around 28 to 32 weeks
This checks that the baby is growing as expected, measures the fluid around it, looks at the placenta, and confirms which way the baby is lying. For many women this is a single scan; for others it is repeated.
A growth scan may be asked for earlier or more often if you have diabetes, high blood pressure, twins, a previous small baby, or if the bump is measuring smaller or larger than expected.
The late scan — 36 weeks onward
A final check on growth, fluid, the baby's position, and the placenta before delivery. Whether the baby is head-down matters for planning the birth, and this is the scan that confirms it.
Some women have an additional Doppler study at this stage — a measurement of blood flow through the cord and the baby's vessels — if there is a concern about growth or if the pregnancy goes past its due date.
Scans not on the routine list during pregnancy
Early viability scans before six weeks are not routine and often cause more worry than reassurance, because a heartbeat may simply not be visible yet.
3D and 4D scans are optional. They produce a more lifelike picture but add no medical information beyond the 2D anomaly scan, and they are not part of standard care.
Extra scans are common and rarely alarming. The usual reasons: a baby measuring slightly small or large, a low-lying placenta that needs re-checking, reduced movements, or a pregnancy running past forty weeks. Your doctor will say why. If you are not told, ask. You are entitled to know.
What a scan cannot do
It cannot see everything. Some conditions do not show on ultrasound, and a normal anomaly scan is reassuring without being a guarantee. It cannot tell you the sex — see above. And it cannot replace the rest of antenatal care: the blood pressure checks, the haemoglobin, the sugar test. The WHO's maternal health guidance frames scans the same way — one part of a whole package of care.
Care at Saroj Hospital
Dr. Deepa Aggarwal, MBBS, DGO, DMRD, DNB (Radiology) sees patients in the gynaecology OPD every day, 10:00 AM–2:00 PM and 5:00–7:00 PM.
She holds qualifications in both obstetrics and radio-diagnosis, which is unusual and practical: the doctor managing your pregnancy is the one performing and reading your scans. Nothing is lost between two departments, and a question at the scan gets answered at the scan.
Blood tests that accompany the scans — the dual marker, quadruple marker and the rest of the antenatal profile — run in our NABL-accredited laboratory, with most reports ready the same day.
Frequently asked questions
How many scans are normal in a pregnancy?
For an uncomplicated pregnancy, usually three to five: the dating scan, the NT scan, the anomaly scan, and one or two in the third trimester. Extra scans are common and usually mean monitoring rather than a problem.
Are pregnancy scans safe for the baby?
Yes. Ultrasound uses sound waves, not radiation, and decades of use have shown no harm to babies. Scans are done when there is a reason, rather than for their own sake, which is why 3D and 4D scans are optional rather than routine.
Do I need a full bladder for the scan?
For early abdominal scans, often yes — a full bladder lifts the uterus into view. For the vaginal dating scan and for later scans, no. Your clinic will tell you when you book.
What if the anomaly scan finds something?
Most findings are minor and are simply watched at a later scan. Where something is significant, your doctor will explain what it means, what the options are, and who else should be involved — with time to think, not in a rush.
Book an appointment
If you are pregnant and have not yet had a dating scan, or you are unsure which scans you are due, book a consultation. The scan and the conversation about it happen in the same room, with the same doctor.
Book an appointment with the gynaecology OPD, or call reception on +91 96676 67011.
Medically reviewed by Dr. Deepa Aggarwal, MBBS, DGO, DMRD, DNB (Radiology), Saroj Hospital, Sonipat.
This article is general health information, not medical advice. For guidance about your own health, please consult a doctor.
Consult Dr. Deepa Aggarwal
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