Understanding Your Pregnancy Ultrasound Timeline

Over a pregnancy you will usually have between three and five ultrasound scans. Each has a specific job, each is done in a strict window, and missing the window matters — some scans (like the NT scan) simply cannot be performed properly later.

The Standard Pregnancy Scan Schedule

Summary of core ultrasound scans and when they are routinely performed:

Scan Name Recommended Window Primary Clinical Purpose
Early / Dating Scan 6 – 9 Weeks Confirms intrauterine pregnancy, heartbeat, number of embryos, and accurate due date.
NT Scan (Nuchal Translucency) 11 Weeks – 13 Weeks 6 Days Screening for chromosomal conditions & early structural evaluation. Strict window.
Anomaly Scan (TIFFA) 18 – 22 Weeks Detailed head-to-toe structural check of baby, placenta, umbilical cord & amniotic fluid.
Growth Scan 28 – 34 Weeks (as needed) Monitors baby’s growth rate, fetal position, fluid volume & placental function.
Colour Doppler Scan When clinically indicated Assesses blood flow in umbilical artery, placenta & fetal circulatory system.

Your obstetrician sets your actual scan schedule. High-risk pregnancies — including twins, gestational diabetes, hypertension, or prior complications — may require additional monitoring scans.

Why No Centre Will Tell You the Baby’s Sex

Compliance with Indian law and the Pre-Conception & Pre-Natal Diagnostic Techniques (PCPNDT) Act:

⚖️ Sex Selection & Disclosure Is Illegal in India

It is strictly illegal in India to determine or disclose the sex of a foetus before birth by any technique — ultrasound, blood test, amniocentesis, or any other method. This is governed by the Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act, 1994, enacted to combat female foeticide and improve the national sex ratio.

What This Means at Your Appointment

Step 1

Government Photo ID Mandatory

You must bring valid government photo ID (such as your Aadhaar card) for identity verification.

Step 2

Form F Documentation

You will complete and sign Form F — a mandatory government record required for every pregnant woman’s ultrasound.

Step 3

Signed Legal Declaration

You will sign a declaration confirming that you are not seeking to determine or disclose the sex of the foetus.

Step 4

Strict Sonologist Compliance

The sonologist will not disclose foetal sex under any circumstances and will not respond to queries or family hints.

🚫 Please Do Not Ask Our Staff

Penalties under the PCPNDT Act are severe — including up to 3 years imprisonment and heavy fines for medical practitioners. Requesting sex disclosure places staff in a legal violation risk and delays patient care. Our team strictly enforces this law to protect female children.

A legally registered diagnostic facility prominently displays its official PCPNDT registration certificate and mandatory prohibition notices. Facilities offering unlawful sex disclosure cut safety and quality corners across all diagnostic procedures.

What Each Scan Actually Does

Detailed breakdown of diagnostic goals for each scan window:

1. Early / Dating Scan (6–9 Weeks)

Confirms that the pregnancy is inside the uterus (ruling out dangerous ectopic pregnancy), confirms heartbeat, determines gestational age, and establishes your due date.

2. NT Scan (11w to 13w 6d)

Measures fluid at the back of baby’s neck (nuchal translucency). Combined with dual marker blood testing, calculates chromosomal risk (e.g., Down syndrome). The 13w 6d window is strict.

3. Anomaly Scan / TIFFA (18–22 Weeks)

Detailed evaluation of baby’s brain, spine, heart, facial profile, kidneys, limbs, placenta position, and amniotic fluid volume.

4. Growth Scan (28–34 Weeks)

Monitors fetal weight growth curves, fetal presentation/position, fluid index, and placental maturity to identify fetal growth restriction (FGR).

🩸 Colour Doppler Evaluation

Assesses blood flow velocity in the umbilical artery, uterine arteries, and baby’s circulation. Requested when there are concerns regarding fetal growth, hypertension, pre-eclampsia, or multiple gestation.

📌 Medico-Legal Understanding: Scan Detection Limitations

No anomaly scan detects 100% of physical abnormalities. Structural visibility depends on fetal position, amniotic fluid volume, and maternal body habitus. A normal scan is highly reassuring but not an absolute guarantee of outcome.

Is Ultrasound Safe in Pregnancy?

Understanding the physics and safety profile of diagnostic ultrasound:

High-Frequency Sound Waves

Diagnostic ultrasound utilizes high-frequency acoustic sound waves, not ionising X-ray radiation. It has an outstanding 50+ year safety record in clinical obstetrics.

Medical Purpose Principle

Scans should always be conducted for valid clinical indications. Non-medical “keepsake 3D/4D videos” without diagnostic benefit are discouraged by international guidelines.

Practical: Preparing for Your Scan

Essential checklist to ensure a smooth, prompt scan appointment:

  • Aadhaar Card / Government Photo ID: Mandatory for Form F completion under the PCPNDT Act.
  • Doctor Prescription & Prior Reports: Comparison with previous scans is crucial for tracking growth curves.
  • Bladder Instructions: Early pregnancy scans (first trimester) usually require a full bladder; mid-to-late trimester scans generally do not. Confirm when booking.
  • Comfortable Clothing: Wear two-piece attire (top and skirt/trousers) for convenient abdominal access.
  • Appointment Timing: Allow 30–45 minutes for detailed anomaly (TIFFA) scans, especially if the baby needs to change position.

🌸 Requesting Female Sonologists / Attendants

Female sonologists and female attendants are available across our centers upon request. Please inform our front desk when scheduling your appointment.

Karauli Diagnostics Centres Across Varanasi

PCPNDT-registered obstetric ultrasound, Colour Doppler, and blood screening across 5 centres:

Bhojubeer Branch (Main Centre)

S.2/326 E-3A, Plot No. 18/1, Gilat Bazar, Bhojubeer, Varanasi, Uttar Pradesh – 221002

Google Maps Directions

Sankat Mochan Branch

B. 36/4-27, Ramapuri Colony, Near Sankat Mochan Temple, Saket Nagar Colony, Varanasi, Uttar Pradesh – 221005

Google Maps Directions

Manduadih Branch

Shop No. 1, MS Commercial Complex, Manduadih Varanasi, Uttar Pradesh – 221005

Google Maps Directions

Maldahiya Branch

C21/30, A1-A2 Pishachmochan Road Near Ganga Palace Maldhaiya, Varanasi, Uttar Pradesh – 221002

Google Maps Directions

Awaleshpur Branch

Amra Chauraha, Above Grihasthi Supermarket, Varanasi, Uttar Pradesh – 221106

Google Maps Directions

🩸 Antenatal Care Package Mention

Explore our Maatritva Suraksha Package for comprehensive blood parameter screening (52+ tests) during pregnancy. Scans are scheduled separately with valid prescription.

Key Takeaways

Summary of essential action points for pregnancy scanning:

1. Strict Scan Windows

Every scan has a window. The NT scan must be performed between 11w and 13w 6d. Missing it narrows your screening options.

2. Anomaly Scan Reassurance

A normal anomaly scan is reassuring but not a 100% guarantee. No imaging detects every congenital condition.

3. Strict PCPNDT Law Compliance

Sex determination is illegal under the PCPNDT Act. Bring Aadhaar ID for mandatory Form F completion.

4. Booking Assistance

Have a scan prescription? Send it on WhatsApp to 70689 70689 or call 70689 70689.

Frequently Asked Questions

Answers to common questions regarding pregnancy ultrasound scans:

Usually three to five in an uncomplicated pregnancy — a dating scan, an NT scan between 11 and 13 weeks 6 days, an anomaly scan around 18 to 22 weeks, and one or more growth scans in the third trimester. More may be needed for twins, diabetes, high blood pressure or if a concern is found. Your obstetrician decides.
Because it is illegal. The PCPNDT Act, 1994 prohibits determining or disclosing the sex of a foetus by any technique in India, enacted to address female foeticide. It applies to every registered facility. Penalties for practitioners include imprisonment of up to three years for a first offence. This is the law, not the centre’s preference.
A government record that must be completed for every ultrasound performed on a pregnant woman under the PCPNDT Act. You will need valid government photo ID such as an Aadhaar card, and you will sign a declaration that the scan is not being done to determine the sex of the foetus. The scan cannot proceed without it.
The nuchal translucency scan measures a fluid space at the back of the baby’s neck and, combined with a blood test, gives a risk estimate for chromosomal conditions. It must be done between 11 weeks and 13 weeks 6 days — the measurement is not valid outside that window.
No. The anomaly scan is a detailed structural examination and a normal result is genuinely reassuring, but no scan detects every abnormality. Detection depends on the condition, the baby’s position, maternal body habitus and fluid volume, and some conditions develop later or are not visible on ultrasound at all. It reduces uncertainty; it does not eliminate it.
Diagnostic ultrasound uses sound waves rather than ionising radiation and has a long record of safe use in pregnancy when performed by trained operators for clinical reasons. Professional bodies discourage non-medical keepsake scanning because exposure without clinical purpose has no benefit to weigh against it.
Commonly for early pregnancy scans, and generally not for later ones. Confirm when you book — this is the most frequent cause of confusion and wasted trips.
This depends on the centre’s policy — ask when booking. You may also request a female sonologist or a female attendant present.
An ultrasound that assesses blood flow in the umbilical cord, placenta and baby’s circulation. It is not routine and is requested when there is a specific concern such as poor growth, placental function, high blood pressure or a twin pregnancy.
Speak to your obstetrician promptly. The NT measurement itself cannot be done after 13 weeks 6 days, but alternative screening approaches exist. The sooner you ask, the more options remain.

Peer-Reviewed & Legal Sources

Statutory guidelines and clinical frameworks cited in this guide:

AS

Medically Reviewed by Dr. Ankita Ujjwal Shah & PCPNDT Compliance Lead

MD, DNB (Consultant Radiologist & Obstetric Sonologist), Karauli Diagnostics · Published: 17 August 2026

This article is for general informational purposes and does not replace advice from your obstetrician. Scan schedules and indications are clinical decisions tailored to your pregnancy.

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