TVS, USG & Level 2 Ultrasound in Pregnancy: A Simple Guide

Not every pregnancy ultrasound answers the same question. TVS (transvaginal ultrasound) uses an internal probe for early pregnancy to capture clearer images; USG (ultrasonography) is simply the medical term for any ultrasound scan, and a Level 2 ultrasound is a detailed anatomy scan done around 18 to 21 weeks^[1]. This article explains each scan type, what to expect, and how to read common report terms. It does not replace your doctor's interpretation of your individual results.

What do TVS, USG and Level 2 ultrasound mean?

Understanding these three terms removes much of the confusion around pregnancy scans.

• USG (Ultrasonography) is the umbrella term for any scan that uses sound waves to create images of your baby^[2]. When your doctor orders a "USG test," they mean an ultrasound examination.
• TVS (Transvaginal Ultrasound) uses a slim, wand-shaped probe inserted into the vagina. Because the probe sits closer to the uterus, it can produce high-resolution, real-time images in the first trimester^[3]. TVS is the imaging modality of choice during early pregnancy for confirming intrauterine pregnancy, assessing fetal viability, and estimating gestational age^[2].
• Level 2 Ultrasound (also called the anomaly scan or 20-week scan) is a detailed examination performed between 18 and 21 weeks. Its main purpose is to examine the baby's anatomy and identify possible structural birth defects that may affect the baby's health and development^[1].

What Happens During a Routine USG Scan in Pregnancy?

Routine ultrasound scans are performed during pregnancy to assess fetal development, estimate gestational age, and screen for certain conditions^[4].

The first scan (around 12 weeks) estimates when your baby is due based on measurements and can include nuchal translucency screening if you choose it. During this scan, a sonographer applies gel to your abdomen and moves a handheld device (transducer) across your skin. The transducer sends sound waves that bounce off internal structures to create images on a monitor^[4].

In early pregnancy, your doctor may recommend a transvaginal approach instead if a clearer view is needed^[3]. Both methods are safe, and there are no known risks to you or your baby from having an ultrasound scan^[5].

What Is a TVS (Transvaginal) Ultrasound Used for in Pregnancy?

TVS is primarily used in the first trimester when abdominal scans may not provide sufficient detail^[3].

Common uses include^[2]:

• Confirming intrauterine pregnancy and assessing for ectopic pregnancy
• Assessing fetal heartbeat and viability
• Estimating gestational age through crown-rump length measurement
• Performing nuchal translucency screening

Which probe is used depends on patient factors such as gestational duration, body weight, and distribution of adiposity. The transvaginal approach may produce better images for patients under 8 weeks of gestation, those with higher BMIs, or those with increased suprapubic adiposity^[6].

Your doctor will determine which approach suits your individual circumstances.

Is TVS Ultrasound Painful?

This is one of the most common concerns expectant mothers have. The short answer: TVS may cause mild discomfort but is generally not painful.

A study was conducted to investigate whether ultrasound parameters could predict the mode of delivery among 252 pregnant women, as well as the discomfort experienced during the transvaginal ultrasound scan. Along with the main findings, most women experience only mild discomfort during TVS. Severe pain is uncommon, and any discomfort is usually brief^[7].

The procedure involves inserting a lubricated, smooth, wand-like probe into the vagina^[8]. Relaxing your pelvic muscles and taking slow, deep breaths can help reduce discomfort. The entire scan typically takes 15 to 20 minutes. If you experience significant pain during the procedure, tell the sonographer immediately so they can make adjustments.

What Is a Level 2 Ultrasound and When Is It Done?

A Level 2 ultrasound, also known as the anomaly scan or 20-week scan, is performed between 18 and 21 weeks of pregnancy^[1]. It is more detailed than routine scans and focuses on checking your baby's physical development.

What the Level 2 scan checks:

The scan screens for 11 different conditions that may affect your baby's health and development^[1]. These include conditions affecting the brain, heart, spine, kidneys, and limbs. The sonographer also checks the placenta's position, amniotic fluid levels, and overall growth.

Detection rates vary between conditions:

• Spina bifida can usually be seen clearly, with about 90% detected at this stage
• Heart defects are harder to see, with about 50% detected^[9]

Some conditions can be seen more clearly than others, so the scan may not find everything ^[1]. If an abnormality is suspected, your doctor will discuss next steps, which may include follow-up imaging or a referral to a specialist.

Discuss any concerns about Level 2 findings with your healthcare provider.

Understanding Your USG Report: Common Terms Explained

Ultrasound reports contain abbreviations that may seem confusing. Here are the most common terms:

CRL is used to assess gestational age between weeks 8 and 14 of pregnancy. After 13 weeks, BPD and head circumference may provide more accurate dating^[10]. These measurements help determine whether your baby is growing as expected^[11].

Remember that USG reports are written for healthcare professionals. Always discuss your report findings with your doctor rather than attempting self-interpretation.

How to Prepare for Your Ultrasound

Preparation differs slightly depending on the scan type.

For abdominal ultrasound (including Level 2 scan):

• You may need a full bladder when you arrive; contact your hospital if unsure
• The scan is performed in a dimly lit room to get clear views of your baby
• Wear comfortable, loose clothing that allows easy access to your abdomen^[1]

For transvaginal ultrasound:

• No special preparation is needed
• Empty your bladder before the test for greater comfort^[12]
• Wear loose, easy-to-remove clothing

Both types of scans are safe. There are no indications that the use of B-mode or M-mode prenatal ultrasonography may be harmful during the first trimester due to their limited acoustic output^[13]. However, scanning time should be limited, and the lowest possible power output should be used.

Conclusion

Understanding the differences between TVS, routine USG, and Level 2 ultrasound can help you feel more prepared for your prenatal appointments. TVS provides clearer early-pregnancy images and typically causes only mild discomfort. The Level 2 scan at 18 to 21 weeks offers a detailed check of your baby's development. Both are considered safe procedures with no known risks to mother or baby. If you have questions about your scan results or what to expect, speak with your healthcare provider, who can offer guidance tailored to your pregnancy.

Medical Disclaimer

This article is for informational purposes only and does not constitute medical advice. The information provided should not be used for diagnosing or treating health conditions. Always consult a qualified healthcare provider for diagnosis, treatment, and personalised medical advice. Do not disregard professional medical advice or delay seeking it because of information found in this article. If you have a medical emergency, contact your doctor or emergency services immediately.