Early pregnancy is a delicate and crucial period that requires accurate monitoring to ensure the health of both mother and baby. Ultrasound scans play an essential role in confirming pregnancy and assessing early fetal development. Among the different ultrasound methods, Transvaginal Scan (TVS) and Abdominal Ultrasound (USG) are commonly used. However, in the first trimester, TVS is often preferred. This article explores what TVS is, why it is done over abdominal USG in early pregnancy, and its advantages.
What is a Transvaginal Scan (TVS)?
A Transvaginal Scan (TVS) is an ultrasound technique where a small, specially designed probe is gently inserted into the vagina. This approach places the probe closer to the uterus, providing clearer and more detailed images of the early pregnancy structures such as the gestational sac, yolk sac, and fetal pole.
Unlike the abdominal ultrasound (USG), where the probe is moved over the abdomen, TVS bypasses the abdominal wall and bladder, which can obscure or reduce the clarity of early pregnancy images.
Advantages of TVS Over Abdominal Ultrasound in Early Pregnancy
TVS offers several critical advantages during the early weeks of pregnancy, typically up to 12 weeks gestation:
- Earlier Pregnancy Detection:
TVS can detect pregnancy as early as 4 to 5 weeks, identifying the gestational sac and fetal pole much earlier than abdominal USG, which usually performs better after 6 weeks. - Sharper, Clearer Images:
Because the probe is closer to the uterus, TVS produces high-resolution images that allow for detailed visualization of early fetal structures, helping in accurate dating and viability assessment. - Better Fetal Heartbeat Detection:
Fetal cardiac activity can be detected earlier and with greater accuracy via TVS, often as early as 5.5 to 6 weeks, which is critical for confirming a viable pregnancy. - Early Complication Assessment:
TVS is the gold standard for diagnosing potential early pregnancy complications such as:- Ectopic pregnancy (implantation outside the uterus)
- Threatened miscarriage
- Subchorionic haemorrhage
- Assessment of Uterine and Ovarian Health:
It allows detailed examination of the uterus, cervix, and ovaries, helping identify fibroids, cysts, or other abnormalities that may affect pregnancy.
When is TVS Recommended?
Your doctor may advise a transvaginal scan in early pregnancy under the following circumstances:
- Confirmation of Early Pregnancy: To verify pregnancy location and viability.
- Vaginal Bleeding or Abdominal Pain: To assess risks such as miscarriage or ectopic pregnancy.
- Inconclusive Abdominal Ultrasound Results: When abdominal USG does not provide clear information.
- History of Previous Pregnancy Complications: To closely monitor pregnancy development.
- High-Risk Pregnancies: To ensure early and precise fetal monitoring.
What to Expect During a TVS?
- The procedure is generally safe and painless.
- The probe is covered with a sterile sheath and lubricated before insertion.
- It usually takes 10-20 minutes.
- No special preparation is required, but a full bladder is generally not needed (unlike abdominal USG).
In early pregnancy, TVS is preferred over abdominal ultrasound due to its superior ability to detect pregnancy earlier, provide clearer images, and identify potential complications promptly. This early and accurate assessment enables better monitoring and management, ensuring the best possible care for mother and baby. If you experience any symptoms or require early pregnancy evaluation, consult your healthcare provider about the benefits of a transvaginal scan.