A scan appointment is not emergency care
Seek Urgent Maternity Assessment for Warning Signs
Contact your obstetric team or emergency service immediately for:
- Heavy vaginal bleeding, fainting, collapse or severe weakness.
- Severe or one-sided abdominal pain, particularly with shoulder-tip pain in early pregnancy.
- Severe persistent pain, fever, repeated vomiting or feeling acutely unwell.
- A gush or continuing leakage of fluid from the vagina.
- Regular painful contractions or symptoms of premature labour.
- Reduced or absent fetal movements after you have established your baby's usual movement pattern.
- Severe headache, visual disturbance, breathlessness, seizures or sudden marked swelling.
Do not wait for a scheduled ultrasound or use a reassuring home Doppler reading to delay care. Emergency assessment may include clinical examination, maternal observations, blood tests, fetal monitoring and ultrasound according to gestation and symptoms.
What is an Antenatal Ultrasound?
An ultrasound probe sends sound waves into the body and receives echoes from tissues and moving structures. A computer converts those echoes into images. The examination can show the uterus, cervix, ovaries when relevant, fetus, placenta, amniotic fluid and selected blood vessels.
Ultrasound does not use the ionising radiation used in X-rays or CT. Diagnostic obstetric ultrasound is generally considered safe when performed for a medical reason by trained professionals using the minimum exposure required to answer the clinical question.
Each Scan Has a Specific Question
A viability scan, NT scan, anomaly scan and growth scan are not interchangeable. The report should be interpreted against the exact gestational age, referral question and earlier results.
Which Pregnancy Scans May Be Recommended?
Not every pregnancy needs every scan. The number and timing of examinations vary with local antenatal protocols, access, multiple pregnancy, maternal conditions, symptoms and prior findings.
What Does an Early Pregnancy or Viability Scan Assess?
An early scan may be requested for pain or bleeding, uncertain dates, previous ectopic pregnancy or miscarriage, fertility treatment, or reassurance when there is a clinical concern. It may be performed through the abdomen, but a transvaginal scan often gives clearer detail early in pregnancy.
The radiologist may assess:
- Whether a pregnancy is visible within the uterus.
- The gestational sac, yolk sac and embryo when each should be visible.
- Embryonic or fetal cardiac activity when expected for the measured stage.
- Crown–rump length and approximate gestational age.
- Whether there is one pregnancy or more than one.
- The uterus, cervix, ovaries, adnexa and any pelvic fluid when clinically relevant.
A scan performed very early may be inconclusive simply because the pregnancy is smaller than expected from menstrual dates. Ovulation can occur later than assumed. A carefully timed repeat ultrasound and serial beta-hCG blood tests may be needed before a reliable conclusion can be made.
If no intrauterine pregnancy is seen, the report may use the term “pregnancy of unknown location.” This is not a final diagnosis. Follow-up is essential because the possibilities include a very early intrauterine pregnancy, a completed miscarriage or an ectopic pregnancy.
What Happens at the Dating and NT Scan?
First-trimester ultrasound uses fetal measurements—most often crown–rump length—to estimate gestational age and the expected date of delivery. Ultrasound dating can differ from the date calculated from the last menstrual period, particularly with irregular cycles or uncertain dates.
The examination may document:
- Fetal cardiac activity, number and basic early anatomy visible at that stage.
- Crown–rump length and pregnancy dating.
- Placental location and relevant uterine or adnexal findings.
- Chorionicity and amnionicity in a multiple pregnancy.
- Nuchal translucency when requested and the fetus is within the validated measurement window.
NT is a screening measurement, not a diagnosis. It estimates the chance of selected chromosomal or structural conditions when interpreted with maternal information and, depending on the chosen pathway, blood tests or cell-free DNA screening. A low-risk result cannot exclude every condition; a higher-chance result does not prove the fetus has a condition.
If screening is desired, timing matters. Speak with the obstetric team early so that the appropriate scan and laboratory tests can be performed within their valid gestational windows.
What Does the Anomaly, TIFFA or Level II Scan Look For?
The detailed mid-pregnancy scan is commonly performed around 18–22 weeks, with the exact timing set by the obstetrician and local protocol. It systematically examines fetal anatomy that can be assessed at this stage rather than providing only a general view of the baby.
The scan also assesses:
- Fetal measurements and whether size is appropriate for gestational age.
- Placental location and its relationship to the cervix.
- Umbilical-cord insertion and vessel number when visible.
- Amniotic-fluid volume.
- Cervical appearance or length when indicated.
- Additional features based on the referral and pregnancy history.
An anomaly scan cannot detect every structural condition, and ultrasound does not diagnose every chromosomal, genetic, developmental or functional disorder. Some conditions develop later, are too subtle to see, or cannot be assessed because of fetal position or technical limitations.
What is Assessed on a Growth or Wellbeing Scan?
A later scan may be advised because of maternal diabetes or hypertension, a multiple pregnancy, previous growth problems, concern about uterine size, reduced movements, placental findings or another obstetric indication. A single measurement estimates size; serial scans show growth over time.
A biophysical profile may combine ultrasound observations of movement, tone, breathing movements and fluid, sometimes with external fetal-heart monitoring. It is requested for specific indications and interpreted with the full maternal and fetal assessment.
When Are Specialist Ultrasound Assessments Used?
How Should I Prepare?
- Follow the preparation instructions given when the appointment is booked.
- Bring the referral or prescription, antenatal record, laboratory reports and all previous scan reports and images.
- Know the first day of your last menstrual period and, if applicable, embryo-transfer or ovulation dates.
- Take prescribed medicines normally unless your treating clinician gives different instructions.
- Wear comfortable clothing that allows the lower abdomen to be exposed while preserving privacy.
- Allow enough time: a detailed scan can take longer when the fetal position limits required views.
Appointment policies for companions, children, photographs and recording vary. A pregnancy scan is a medical examination requiring concentration, so confirm the hospital policy before bringing others.
What Happens During an Abdominal Scan?
The radiologist confirms your name, pregnancy dates, reason for scanning, symptoms and relevant history and reviews previous examinations.
The lower abdomen is exposed while the rest of the body remains covered. Position may be adjusted for comfort, particularly later in pregnancy.
Water-based gel removes air between skin and probe. Gentle pressure and different angles obtain the required views; tell the radiologist if any area is painful.
The examination may become quiet while the radiologist concentrates. Silence does not mean that a problem has been found.
Gel is wiped away and a formal report is prepared. Important or unexpected findings may require discussion with your obstetrician or a fetal-medicine specialist.
What Should I Expect From a Transvaginal Scan?
Transvaginal ultrasound places a slim covered probe a short distance inside the vagina. Because it sits closer to the uterus, it often provides clearer images in early pregnancy and more accurate assessment of the cervix or a low placenta. It does not enter the cervix or touch the pregnancy.
- The reason, process and alternatives should be explained before you consent.
- You are usually asked to empty your bladder and undress from the waist down in privacy.
- You are covered with a sheet, and a chaperone is provided according to clinical policy and preference.
- The disinfected probe is covered and lubricated before gentle insertion.
- You remain in control and can ask the examination to pause or stop at any time.
The examination may feel uncomfortable but should not be sharply painful. Transvaginal scanning is not known to cause miscarriage. Tell the radiologist about severe pain, active heavy bleeding, latex allergy, inability to tolerate insertion or any concern about the examination.
Why Might the Scan Take Longer or Need Repeating?
Image quality and completion can be affected by:
- Pregnancy being earlier or later than expected.
- The fetus facing away from the required view or remaining in one position.
- Multiple pregnancy, reduced amniotic fluid or placental position.
- Maternal body tissue, abdominal tenderness, fibroids or previous surgical scars.
- A full bladder that is inadequate or, occasionally, too uncomfortable.
- A finding that requires confirmation, additional views or specialist assessment.
You may be asked to walk, change position, empty your bladder or return after an interval. An incomplete examination does not itself mean that something is wrong; it means the required anatomy was not seen well enough to report confidently.
How Do I Read Common Report Terms?
Do not interpret one number or centile in isolation. Trends, measurement quality, Doppler findings, maternal health and the obstetric examination determine whether follow-up is required.
If your baby remains breech in late pregnancy, the newborn team may recommend an infant hip ultrasound after birth even when delivery is by caesarean section.
What Happens if a Finding Needs More Assessment?
The radiologist may repeat a view, ask a colleague for a second opinion or recommend a targeted examination. The obstetrician then combines the ultrasound result with medical history, examination, screening and laboratory information.
Possible next steps include:
- A repeat scan after an appropriate interval.
- A detailed fetal-medicine or fetal-echocardiography appointment.
- Genetic counselling and discussion of screening or diagnostic testing.
- Closer growth, fluid, cervical or Doppler surveillance.
- Changes to maternal treatment, antenatal monitoring, delivery location or newborn-care planning.
An ultrasound “marker” is not always an abnormality and does not by itself establish a genetic diagnosis. Ask what was seen, how certain the finding is, what it may mean and what the next test can clarify.
Can the Fetal Sex Be Disclosed?
No. In India, prenatal sex determination and communication of the sex of the fetus are prohibited under the Pre-Conception and Pre-Natal Diagnostic Techniques (Prohibition of Sex Selection) Act. The hospital does not perform ultrasound for sex determination and will not disclose fetal sex.
The purpose of antenatal ultrasound is medical: assessing pregnancy location, dates, anatomy, growth, placenta, fluid and wellbeing. Requests or pressure to reveal fetal sex cannot be accommodated.
Myth vs Fact
Frequently Asked Questions
Is ultrasound safe during pregnancy?
Diagnostic ultrasound is generally considered safe when used for a medical indication by a trained professional. The operator limits output and examination time to what is needed to obtain useful diagnostic information. Non-medical keepsake scanning is discouraged.
Do I need a full bladder?
Only for selected examinations, particularly some early transabdominal scans. Later scans and transvaginal examinations often need an empty bladder. Follow the instructions given for your appointment rather than filling your bladder automatically.
Can I eat before an antenatal scan?
Yes, in most cases. Fasting is not routinely required for obstetric ultrasound. If another abdominal examination or procedure is planned at the same visit, you may receive different instructions.
Why was no heartbeat seen on my very early scan?
The pregnancy may be earlier than menstrual dates suggest, or the examination route and image quality may limit what is visible. The radiologist uses strict measurement criteria and may recommend a repeat scan rather than making an uncertain diagnosis too soon.
Why did my estimated due date change?
First-trimester fetal measurements can date a pregnancy more accurately than an uncertain last menstrual period. Once an official due date is established, later size differences usually describe growth rather than repeatedly changing the pregnancy date.
Does an NT scan diagnose Down syndrome?
No. Nuchal translucency contributes to a screening estimate. Screening identifies higher or lower chance; diagnostic tests such as chorionic-villus sampling or amniocentesis answer a different question and require individual counselling.
Why could the anomaly scan not be completed?
Fetal position, gestational age, placental location, amniotic fluid and technical factors can prevent certain structures from being seen clearly. A repeat appointment is often simply needed to complete the required views.
Can I record the scan or receive pictures?
Policies vary. The radiologist must prioritise the medical examination, accurate documentation and patient privacy. Ask the hospital before the appointment about companions, photographs or recordings.