Essential Pregnancy Scans You Should Take for a Healthy Baby
BN Clinic 19, Elgin, Kolkata
Fetal Medicine & Maternal Health
www.bnclinic19.com
Every expectant mother deserves to know that her baby is growing well. Pregnancy scans are not just routine checkpoints — they are powerful diagnostic windows that allow your doctor to monitor fetal development, detect abnormalities early, and ensure both mother and baby are safe. Here is a complete trimester-by-trimester guide to the essential pregnancy scans you should not miss.
Why pregnancy scans matter
Ultrasound scans during pregnancy are safe, non-invasive, and use sound waves — not radiation — to create images of your baby inside the womb. They give your fetal medicine specialist a detailed picture of your baby’s anatomy, growth, position, and wellbeing at every stage of pregnancy. Missing key scans means missing the chance to detect and manage conditions early, when intervention is most effective.
Trimester-by-trimester scan guide
Each trimester has specific scans designed for what matters most at that stage of your baby’s development.
First trimester — weeks 6 to 13
6–8
weeks
Early viability scan (dating scan)
Confirms the pregnancy is intrauterine (inside the uterus), detects the fetal heartbeat, estimates gestational age, and rules out ectopic pregnancy. Especially important if you have had a previous miscarriage or fertility treatment.
11–13
weeks
NT scan — Nuchal Translucency scan
One of the most critical first-trimester scans. Measures the fluid at the back of the baby’s neck (NT thickness) to assess risk for chromosomal conditions like Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), and Patau syndrome (Trisomy 13). Often combined with a blood test (Double Marker / PAPP-A) for higher accuracy.
11–13
weeks
First trimester anomaly screening
Also performed at 11–13 weeks, this checks early fetal anatomy including nasal bone, heart structure, and blood flow through the ductus venosus — all markers for chromosomal abnormalities.
Important: The NT scan must be performed between 11 weeks 2 days and 13 weeks 6 days — timing is critical. Book your appointment in advance to avoid missing this window.
Second trimester — weeks 14 to 27
18–22
weeks
Anomaly scan (TIFFA scan / Level II ultrasound)
The most comprehensive structural scan of pregnancy. Examines all major fetal organs — brain, spine, heart, kidneys, abdomen, limbs, and face — to detect structural abnormalities. Also assesses placental position, amniotic fluid levels, and fetal growth. This scan is mandatory for every pregnancy.
18–22
weeks
Fetal echocardiography
A specialised scan focusing exclusively on the baby’s heart. Recommended for mothers with a family history of heart defects, diabetes, or if the anomaly scan raises any cardiac concerns. Evaluates the four heart chambers, valves, and major vessels.
20–24
weeks
Cervical length assessment
A transvaginal scan that measures the length of the cervix. A short cervix is a risk factor for preterm labour. Early detection allows timely intervention such as cervical cerclage or progesterone therapy to prolong the pregnancy safely.
24–28
weeks
Growth scan with Doppler study
Measures fetal size and weight, and uses Doppler technology to assess blood flow through the umbilical cord and placenta. Identifies intrauterine growth restriction (IUGR) — a condition where the baby is not growing at the expected rate — which can have serious implications if undetected.
Third trimester — weeks 28 to 40
28–32
weeks
Third trimester growth scan
Tracks fetal growth velocity, estimated fetal weight, and amniotic fluid volume. Confirms that the baby is on track and the placenta is functioning well. Identifies late-onset IUGR or macrosomia (an unusually large baby).
32–36
weeks
Colour Doppler scan
Assesses blood flow in the umbilical artery, middle cerebral artery, and ductus venosus to evaluate fetal wellbeing and placental function. Critical for high-risk pregnancies with conditions like pre-eclampsia, gestational diabetes, or IUGR.
36–40
weeks
Biophysical profile (BPP) & presentation scan
Evaluates five parameters of fetal wellbeing: breathing movements, body movements, muscle tone, amniotic fluid, and heart rate reactivity. Also confirms the baby’s position (head-down or breech) to help plan delivery.
Special scans for high-risk pregnancies
Some pregnancies require additional monitoring beyond the routine schedule. Your fetal medicine specialist may recommend the following if you have risk factors such as advanced maternal age (above 35), a previous pregnancy with complications, twins or multiple pregnancies, gestational diabetes, hypertension, thyroid disorders, or a family history of genetic conditions.
These include Non-Invasive Prenatal Testing (NIPT) — a blood test from 10 weeks onward that screens for chromosomal conditions with very high accuracy — as well as Amniocentesis or Chorionic Villus Sampling (CVS) for definitive genetic diagnosis when screening tests suggest a risk. 3D and 4D ultrasounds offer detailed structural imaging and real-time fetal movement assessment when standard scans need further clarification.
Note for high-risk mothers: If you are above 35, carrying multiples, or have a pre-existing medical condition, please consult a fetal medicine specialist — not just a general obstetrician — for a tailored scan schedule. Early specialist involvement significantly improves outcomes.
Are pregnancy scans safe?
Yes — diagnostic ultrasound scans used during pregnancy have an excellent safety record spanning over five decades of clinical use. They use high-frequency sound waves, not ionising radiation, and have not been shown to cause any harm to the mother or baby when performed by a qualified professional for clinical reasons. The number of scans recommended in this guide is based on clinical necessity, not excess.
Frequently asked questions
How many scans are needed during a normal pregnancy?
A minimum of 3–4 scans is recommended for a low-risk pregnancy: the dating scan, NT scan, anomaly scan, and at least one third-trimester growth scan. High-risk pregnancies may need 8–12 or more scans across all three trimesters.
Can I skip the NT scan if I feel fine?
No. The NT scan is a screening test — it is not about how you feel. Chromosomal conditions like Down syndrome show no outward symptoms in the mother. Skipping it means missing the only early opportunity to assess this risk.
What is TIFFA and why is it called “Level II”?
TIFFA stands for Targeted Imaging for Fetal Anomalies. It is called Level II because it is a more detailed, targeted scan compared to a basic Level I ultrasound. It is performed by a fetal medicine specialist and examines each organ system systematically.
Is NIPT better than the NT scan?
They serve different purposes. NIPT is a blood test with higher sensitivity for chromosomal conditions, while the NT scan also evaluates structural anatomy and other markers. Many specialists recommend both together for the most complete first-trimester picture.
When should I visit a fetal medicine specialist?
Ideally from 11 weeks onward for the NT scan. If you have any risk factors, consult a fetal medicine specialist as early as 6–8 weeks so a personalised scan and monitoring plan can be put in place from the start.
Your pregnancy, our priority
At BN Clinic 19, our fetal medicine services are designed to give every mother the most accurate, compassionate, and timely care possible. From early viability scans to detailed anomaly assessments and high-risk pregnancy monitoring, our team is equipped with advanced ultrasound technology and the clinical expertise to guide you through every week of your pregnancy with confidence.
Book your pregnancy scan consultation today
BN Clinic 19, Elgin, Kolkata — Expert fetal medicine care for every stage of your pregnancy
