IG Scan in Pregnancy: What It Checks and When It Matters
IG scan in pregnancy can feel confusing when a report mentions growth charts, estimated weight, or fetal measurements. Many expectant parents worry that the scan signals a problem, while others are unsure how it differs from a routine ultrasound. An IG scan generally refers to an ultrasound assessment that uses the International Growth chart approach to compare a baby’s growth with expected patterns for the pregnancy stage. It may help the treating doctor review growth, anatomy, fluid, and other findings, depending on the reason for the scan. Kamineni Fertility Centre advises patients to read the report with their obstetrician rather than interpret one measurement alone. This guide explains the scan’s purpose, timing, preparation, report terms, and difference from Doppler, so you can ask focused questions at your next appointment.
Key takeaways
- An IG scan uses ultrasound measurements to assess fetal growth against expected pregnancy patterns.
- One estimated weight or measurement does not by itself confirm a growth problem.
- Doppler examines blood flow, while a growth scan focuses mainly on size and related ultrasound findings.
- Your obstetrician decides whether an IG scan is needed based on your pregnancy and earlier findings.
- Consult a qualified healthcare professional for medical decisions.
What does an IG scan in pregnancy check?
An IG scan in pregnancy is an ultrasound assessment that compares fetal measurements with expected growth patterns for the stage of pregnancy. The scan may include the baby’s head, abdomen, and thigh bone measurements, along with estimated fetal weight. The sonographer may also review fetal activity, amniotic fluid, placenta, and presentation when clinically relevant.
The term IG may refer to an International Growth chart approach used to assess fetal size. Chart selection can differ between services, so ask which chart and gestational age were used in your report. Growth is interpreted over time, not from one number in isolation.
| Scan feature | What it helps assess |
|---|---|
| Head measurement | Fetal head size compared with the pregnancy stage. |
| Abdominal measurement | Abdominal growth, which can influence estimated fetal weight. |
| Thigh bone measurement | Long-bone growth and proportional development. |
| Estimated fetal weight | A calculated estimate based on several ultrasound measurements. |
Research using International Growth charts has examined how ultrasound estimated fetal weight relates to birth weight, but estimates are not the same as a newborn’s measured weight. National Institutes of Health information on fetal growth charts describes this relationship in a specific research setting.
Patients who are also planning fertility care may find it useful to understand In-vitro Fertilization (IVF), although an IG scan is a pregnancy ultrasound and not an infertility treatment.
When might a doctor advise an IG scan?
An IG scan may be advised when your obstetrician wants to assess fetal growth, follow an earlier measurement, review fluid or placental findings, or monitor a pregnancy with added clinical concerns. The exact timing depends on your medical history, gestational age, symptoms, and previous scan results.
Ultrasound before 24 weeks can help estimate gestational age and identify multiple pregnancy or some fetal anomalies. The World Health Organization guidance on imaging ultrasound before 24 weeks describes these uses. A later growth assessment answers a different question, mainly whether measurements are following an expected pattern.
| Reason for review | What the clinician may examine |
|---|---|
| Size concerns | Measurements, estimated weight, and growth pattern over time. |
| Pregnancy dating | Gestational age using the most suitable earlier information. |
| Fluid or placenta findings | Amniotic fluid and placental appearance within the scan’s scope. |
| Multiple pregnancy | Individual growth and findings for each fetus. |
A doctor may ask for a repeat scan if the measurements do not fit the expected pattern or if earlier results need confirmation. A repeat appointment does not automatically mean that a serious condition is present. Ask what question the next scan is intended to answer.
For patients managing pregnancy risks such as infection, treatment decisions must come from the treating clinician. Kamineni Fertility Centre’s information on Malaria in Pregnancy Treatment: Safe Steps by Trimester should not replace an individual medical review.
How is an IG scan different from a Doppler scan?
An IG growth assessment mainly reviews fetal size and related ultrasound findings, while Doppler ultrasound examines blood flow in selected vessels. They can be requested together because they answer different clinical questions.
| Feature | IG growth assessment | Doppler assessment |
|---|---|---|
| Main focus | Fetal measurements and estimated growth. | Blood flow in selected maternal or fetal vessels. |
| Typical question | Is the baby’s size following an expected pattern? | Does blood flow provide extra information about placental or fetal circulation? |
| Report terms | Measurements, centiles or percentiles, and estimated weight. | Flow indices and vessel-specific observations. |
| Why it may be combined | Growth and circulation can provide different pieces of information. | Doppler may add context when growth or placental function needs review. |
A growth scan cannot replace Doppler when your clinician specifically needs blood-flow information. Likewise, Doppler does not replace measurements of fetal size. Read Growth Scan vs Doppler Scan: What Each Test Shows for a focused comparison of these assessments.
Do not compare your report with another pregnant person’s report. The correct interpretation depends on gestational age, earlier scans, maternal health, fetal number, and the chart used.
How should you prepare for an IG scan and read the report?
Preparation depends on gestational age and the imaging centre’s instructions, so follow the appointment guidance you receive. Wear clothing that allows the abdomen to be examined comfortably and bring earlier scan reports when requested.
During the appointment
- The sonographer records measurements using ultrasound equipment.
- The examination may include fetal position, movement, placenta, and fluid observations.
- The scan may take longer if the baby’s position limits clear views.
- The final clinical meaning is discussed by the obstetrician or qualified healthcare professional.
Terms patients often see
- Gestational age: the pregnancy age used to compare the measurements.
- Estimated fetal weight: a calculated estimate, not a direct weighing of the baby.
- Percentile or centile: a position within a reference growth pattern.
- Growth trend: how measurements change across scans.
Ask whether the report shows a single measurement or a pattern across more than one scan. Also ask which findings require action now, which need monitoring, and when the next review is planned. If you have a complex fertility history, your care team may also discuss earlier treatment records, including Ovulation Induction or other assisted conception details.
Pregnancy after fertility treatment can involve extra questions, but an IG scan still needs interpretation according to the current pregnancy findings. A consultation with Best Fertility Centre in Hyderabad follows the same planning steps of reviewing your history, scan findings, and next care decision.
What should you ask after an IG scan?
After an IG scan, ask what the measurements show, whether growth follows the expected pattern, and whether any repeat scan or Doppler assessment is advised. These questions help turn a technical report into a clear care plan.
- Which growth chart was used for this report?
- What is the estimated fetal weight, and how should I understand it?
- Are the measurements proportionate for the gestational age?
- Do I need a repeat growth scan or Doppler assessment?
- Which symptoms should prompt an urgent call?
- When will the report be reviewed with me?
Ultrasound is performed by trained professionals, and the scan is not a substitute for clinical examination or ongoing antenatal care. If you are uncertain about a finding, contact your obstetrician rather than relying on online comparisons. Consult a qualified healthcare professional for medical decisions.
An IG scan uses ultrasound measurements to review fetal growth and related findings. The report should be read with gestational age, earlier scans, and the chart used, not as one isolated number. Doppler is different because it assesses blood flow. Write down your questions about estimated weight, growth trend, repeat scans, and Doppler before your appointment. For help arranging a fertility or pregnancy consultation, contact Kamineni Fertility Centre on +91 94910 68784. Consult a qualified healthcare professional for medical decisions.
FAQs
What is an IG scan in pregnancy?
An IG scan in pregnancy is an ultrasound assessment that compares fetal measurements with expected growth patterns for the pregnancy stage. It may review estimated fetal weight, head, abdomen, thigh bone, fluid, placenta, and other findings.
Is an IG scan the same as a growth scan?
An IG scan is generally a type of growth-focused ultrasound assessment using an International Growth chart approach. The exact report format and chart can vary, so ask your doctor which method was used.
Is an IG scan the same as a Doppler scan?
An IG scan mainly assesses fetal size and growth patterns, while a Doppler scan assesses blood flow in selected vessels. A doctor may request both because they provide different information.
When is an IG scan done in pregnancy?
An IG scan may be done when a clinician wants to assess fetal growth, follow an earlier measurement, or review a pregnancy concern. The timing depends on gestational age, medical history, and previous findings.
Does an abnormal IG scan confirm a problem?
An unusual IG scan measurement does not by itself confirm a serious problem. Your obstetrician considers growth trends, gestational age, symptoms, fluid, placenta, and other findings before deciding what happens next.
How should I prepare for an IG scan?
Follow the imaging centre’s instructions because preparation can vary with gestational age and the scan type. Bring earlier reports when requested and wear clothing that allows comfortable abdominal examination.
