The Dating and Viability Scan is an early ultrasound performed around 6–8 weeks of pregnancy to confirm and assess the health of the pregnancy.  Its importance lies in providing accurate information for pregnancy dating and confirming viability, ensuring proper care and planning for the weeks ahead. The Dating and Viability Scan establishes key details such as the presence of a fetal heartbeat, the number of embryos, and the estimated gestational age by measuring the crown-rump length (CRL). This scan ensures the pregnancy is developing inside the uterus (not ectopic) and helps identify potential issues early. This makes this the most important scan that sets the stage for a healthy pregnancy outcome (both maternal and fetal health).  

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Procedure:

• Typically done transvaginally (internal ultrasound) for clearer images, especially in early pregnancy.
• A transabdominal ultrasound may be used, though it is less precise at this stage

Preparation:

• You may be asked to have a moderately full bladder to improve image clarity.
• This scan is vital for establishing the pregnancy's health and timeline, ensuring proper management in the early stages.

 

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Is a Dating and Viability Scan the same as an Early Pregnancy Scan?

A dating and viability scan and an early pregnancy scan are both ultrasound scans performed during the first trimester of pregnancy, but they have slightly different focuses and purposes:

 

Dating and Viability Scan	Early Pregnancy Scan
Purpose: To confirm the viability of the pregnancy (presence of a fetal heartbeat). To determine the gestational age of the fetus and estimate the due date. To check for the number of fetuses (single or multiple pregnancies). To assess early fetal development and detect major abnormalities.	Purpose: Often used more broadly to check the overall status of the pregnancy. May assess viability, but the emphasis could vary depending on the timing or reason for the scan (e.g., suspected complications).
Timing: Usually done between 7 to 12 weeks of pregnancy.	Timing: Typically performed before 7 weeks or earlier in pregnancy if there are specific concerns such as bleeding, cramping, or a history of complications.
Why It's Done: Accurate dating of the pregnancy helps guide further prenatal care. It confirms that the pregnancy is progressing normally and rules out early complications like missed miscarriage or ectopic pregnancy.	Why It's Done: To confirm pregnancy location (e.g., to rule out ectopic pregnancy). To check for any issues, such as subchorionic hematoma or anembryonic pregnancy. To reassure the mother if there are symptoms like spotting or pain.

Key Differences:

1. Focus:
   • Dating and viability scans emphasize accurate gestational dating and confirming fetal viability.
   • Early pregnancy scans focus on diagnosing and managing concerns in the very early stages of pregnancy.
2. Timing:
   • Dating and viability scans occur slightly later (7–12 weeks), while early pregnancy scans are often done earlier.

Both scans use transabdominal or transvaginal ultrasound and are key in ensuring the pregnancy is healthy and progressing as expected.

 

Importance of Dating and Viability Scan :

 

During a Dating and Viability Scan (6–8 weeks), several potential issues or risks can be identified, including:

1. Ectopic Pregnancy: Occurs when the embryo implants outside the uterus, often in a fallopian tube. It can be life-threatening if not treated promptly.

2. Miscarriage (Pregnancy Loss): May be indicated by the absence of a fetal heartbeat or an embryo smaller than expected for gestational age.

3. Blighted Ovum (Anembryonic Pregnancy): A condition where the gestational sac develops, but the embryo does not form or stops developing.

4. Molar Pregnancy: A rare condition where abnormal tissue, instead of a fetus, grows inside the uterus.

5. Subchorionic Hematoma: A collection of blood between the uterine wall and the gestational sac, which may increase the risk of miscarriage but often resolves on its own.

6. Multiple Pregnancies: Confirms if twins, triplets, or higher-order multiples are present, which may carry higher risks such as preterm birth or growth complications.

7. Incorrect Gestational Age: If the pregnancy is earlier or later than expected, it may require adjustment of the due date.

8. Abnormal Gestational Sac or Yolk Sac: An irregularly shaped gestational sac or an absent/enlarged yolk sac can indicate potential complications.

Identifying these issues early helps guide appropriate medical care and intervention, improving outcomes for both mother and baby. Therefore as soon as you find that you are pregnant it is important to immediately book a consultation with your obstetrician.