Viability Ultrasound
Your First Confirmation of Pregnancy
You have just found out that you are pregnant. The pregnancy test is positive, and you may be feeling a mix of joy, anticipation, and perhaps a little anxiety. Is everything okay? Is the pregnancy developing normally? Is it located where it should be?
A viability ultrasound is the first answer to all of these questions. It is usually performed between the 5th and 8th week of pregnancy and is the first essential step in monitoring any pregnancy, especially those conceived after IVF or other assisted reproduction methods.
A viability ultrasound is the first “glimpse” — confirmation that the pregnancy is present, correctly located, and developing.
When is a viability ultrasound performed?
The ideal time for a viability ultrasound is between the 5th and 8th week of pregnancy, which is approximately 1–4 weeks after the first missed period.
From the 6th week onward, it is usually possible to detect cardiac activity, one of the most important signs of viability. At 5 weeks, the yolk sac is usually visible, but the fetal pole and cardiac activity may not yet be seen — and this is completely normal.
There are, of course, cases in which the ultrasound is scheduled earlier or more urgently:
- After IVF, when the exact gestational age is known and monitoring begins early
- In women with a history of miscarriage or previous ectopic pregnancies
- When there are symptoms such as spotting, bleeding, or abdominal or pelvic pain
- In high-risk pregnancies due to age or underlying medical conditions
How is the examination performed?
A viability ultrasound is performed transvaginally — using a thin, specially designed probe that is gently inserted into the vagina. This method is chosen because, at such an early stage of pregnancy, the transvaginal approach provides clearly superior image resolution compared with an abdominal ultrasound.
The examination is painless, safe for the embryo, and usually lasts 10–15 minutes. No special preparation is required — there is no need for a full bladder, as with an abdominal ultrasound.
What is assessed during a viability ultrasound?
Although the embryo at this stage is only a few millimetres in size, the information obtained from this examination is critical:
Location of the pregnancy
The first and most important question: is the pregnancy inside the uterus? An ectopic pregnancy — most commonly tubal — is a serious, potentially dangerous condition that requires immediate attention. Early diagnosis by ultrasound is vital.
Fetal cardiac activity
From the 6th week onward, an attempt is made to detect cardiac activity. The embryonic heart normally beats at around 90–110 beats per minute at 6 weeks, rising to 140–170 beats per minute around the 9th week. Detection of cardiac activity is a strong indicator of a viable pregnancy.
Gestational age & estimated due date
We measure the embryo’s crown–rump length (CRL), which allows us to calculate gestational age accurately and estimate the due date — particularly useful when menstrual cycles are irregular.
Number of embryos
We confirm whether this is a singleton or multiple pregnancy. In twin pregnancies, we also assess whether the babies share the same placenta and/or amniotic sac or have separate ones — a distinction with important prognostic and clinical implications for follow-up.
Yolk sac & fetal pole
We assess the yolk sac and the fetal pole — the early structures from which the embryo develops. Their normal development is a positive prognostic sign.
Uterus and ovaries At the same time, we assess the uterus and ovaries for the presence of fibroids, cysts, or other findings that could affect the course of the pregnancy — such as a corpus luteum cyst, which is normal and gradually resolves.
What does it mean if cardiac activity is not detected?
This is often the first question women ask when they come in for this examination.
The absence of cardiac activity does not automatically mean there is a problem, especially if the scan is performed early, at 5 weeks or at the beginning of the 6th week. In these cases, the pregnancy may be completely normal but still too early for cardiac activity to be visible.
Usual practice: we repeat the ultrasound 7–10 days later. In most cases, cardiac activity is then clearly visible on the follow-up scan.
If there is still no cardiac activity on repeat examination, or if an anembryonic pregnancy is diagnosed (a sac without an embryo), we evaluate all findings together and discuss the next steps.
The management of an early pregnancy loss requires an individualised approach, and this is an integral part of the care we provide.
Viability ultrasound after IVF
For couples who achieved pregnancy through IVF, this examination carries particular emotional and clinical significance. It is usually scheduled about 2–3 weeks after embryo transfer, that is, around the 6th–7th week of pregnancy.
In these cases, the examination is part of a structured monitoring protocol, alongside checks of β-hCG and progesterone levels, assessment of the response to medication support, and close communication with the doctor at every step.
Frequently Asked Questions (FAQ)
Not really. For a transvaginal ultrasound, a full bladder is not required — in fact, it is usually more comfortable if the bladder is relatively empty. If you are taking medication (for example, progesterone after IVF), continue it as usual and mention it during the examination.
No, they are two different examinations. A viability ultrasound is performed early, at 5–8 weeks, and its purpose is to confirm that the pregnancy is intrauterine and viable. The first-trimester scan (nuchal translucency scan) is performed later, between 11 and 14 weeks, and focuses on prenatal screening for chromosomal abnormalities.
Yes, absolutely. Diagnostic ultrasound does not use radiation — it is based on low-intensity sound waves, which have no documented harmful effect on the embryo or the mother when used appropriately in clinical practice. It has been used safely for decades at all stages of pregnancy.
Yes — in fact, in this situation it is particularly important to have the examination promptly. Spotting in early pregnancy does not necessarily mean there is a problem, but serious causes — such as ectopic pregnancy or threatened miscarriage — need to be ruled out. Do not delay; contact your doctor promptly.
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