Ultrasound is one of the most used tools in fertility care. A scan can count the small follicles in your ovaries, track how eggs grow during treatment and check the womb lining. It uses sound waves, not radiation, and you can usually see the screen as it happens.
What it is
An ultrasound scan uses high-frequency sound waves to build a live picture of organs inside the body. For fertility, the scan is usually done with a slim probe placed in the vagina, which sits close to the womb and ovaries.
| Scan type | What it shows | When |
|---|---|---|
| Antral follicle count | Small 2–10 mm follicles; an estimate of egg supply | Early cycle, typically the first few days |
| Follicle tracking | Growth of follicles and the womb lining | Repeated during IUI or IVF |
| 3D scan of the womb | Shape of the womb cavity and outline | During a fertility work-up |
3D ultrasound images can be stored and reviewed again later without radiation, and studies show close agreement with MRI when diagnosing differences in womb shape.
Who it's for
- Anyone having a fertility assessment
- People timing intercourse or IUI around ovulation
- People having ovarian stimulation for IVF or egg freezing
- People being checked for differences in the shape of the womb
For IUI, ovulation can be pinpointed with home LH kits, blood tests or transvaginal ultrasound. Insemination usually follows 24–36 hours after the LH surge or an hCG trigger injection.
Outside fertility treatment, Cleveland Clinic lists other reasons for a vaginal scan: looking for the cause of pelvic pain or irregular bleeding, checking for cysts, fibroids or polyps, confirming where a pregnancy is, and checking the position of a coil (IUD).
Step by step
- Baseline scanEarly in the cycle, the doctor checks the womb and counts antral follicles in each ovary.
- Starting treatmentIf you are having stimulation, medicines start. In IVF, stimulation typically lasts 8–14 days.
- Tracking scansRepeat scans, often with blood tests, measure the size of growing follicles and the thickness of the lining.
- Choosing the momentWhen follicles are ready, a trigger injection is given. IVF egg collection follows about 36 hours later.
- ProcedureIUI is timed to ovulation, or eggs are collected with ultrasound guidance.
During IVF, ultrasound scans and blood tests are used together, to track how the follicles develop and how your hormone levels change from day to day.
What it feels like
You lie on a couch and a slim, lubricated probe with a cover is gently placed in the vagina. It can feel uncomfortable as it goes in or moves, but should not be painful. You can ask to insert it yourself, and you can ask to stop at any time.
- You lie on your back with knees bent and legs apart; your feet may rest in stirrups.
- The probe is slim, less than 1.5 inches (about 4 cm) across, and covered with a sterile cover and gel.
- You may feel pressure or mild discomfort, but it should not be painful.
- A little discharge from the gel is possible within 24 hours.
No anaesthesia or recovery time is needed. NHS guidance says ultrasound scans generally take 10 to 45 minutes; follicle tracking scans are often at the shorter end.
Cleveland Clinic says a vaginal scan takes about 15 to 30 minutes, depending on what the doctor is looking for. If the doctor scans you, results may be discussed the same day; a full written report can take a few hours to a few days.
If you feel anxious about internal scans, tell the team before you start. They can explain each step and go at your pace.
How to prepare
- Note the first day of your period so scans can be booked on the right day
- Wear comfortable, two-piece clothing
- Ask whether you need an empty or full bladder
- Ask the doctor to show you the follicles on screen
- Don't skip tracking scans during stimulation
- Don't compare your follicle numbers with other people's
A scan can be done during your period. Cleveland Clinic advises removing a tampon beforehand, and following instructions about drinking and using the toilet, because a full or empty bladder changes how organs look on screen.
Risks and limits
Ultrasound is considered safe: it uses sound waves and does not involve radiation. The main downside is temporary discomfort from the probe.
Cleveland Clinic describes vaginal ultrasound as safe, including during pregnancy.
- Antral follicle counts depend on the experience of the person scanning
- A follicle count estimates egg numbers but cannot show egg quality
- Ovarian reserve results cannot tell who will or will not conceive
Many follicles growing during stimulation can be a sign of a strong response, so your team uses the scans to adjust treatment and watch for over-response.
| Question | Answer |
|---|---|
| Does it use radiation? | No, it uses sound waves |
| Is anaesthesia needed? | No |
| Can I go straight back to my day? | Yes |
How DBN does it
DBN offers 4D ultrasound. The research we cite describes 3D ultrasound, which can show a frontal (coronal) view of the womb that standard 2D scans usually cannot, helping to tell apart differences in womb shape.
- 4D ultrasound: approximately 2,500–4,500 THB, about 20–30 minutes
- The first consultation is free; prices are confirmed at consultation
When to see a doctor
- You want a fertility check that includes your ovaries and womb
- Your periods are irregular, very painful or very heavy
- You are starting IUI, IVF or egg freezing
- You have severe bloating or pain during stimulation
Questions & answers
Is a transvaginal scan painful?
It can feel uncomfortable, but it should not hurt. You can ask the person scanning to stop at any time.
How many scans will I need during treatment?
It varies with your response to medicine. Your clinic will plan scans based on how your follicles grow.
Does ultrasound use radiation?
No. It uses sound waves, unlike X-rays or CT scans.
Related DBN services
Related articles
Sources
- Ultrasound scan — NHS
- Ovarian reserve: predicting fertility potential in women — ASRM ReproductiveFacts
- In Vitro Fertilization Treatment Journey — ASRM ReproductiveFacts
- IUI (Intrauterine Insemination): Procedure & Results — Cleveland Clinic
- Application of 3D Ultrasonography in Detection of Uterine Abnormalities — PMC (peer-reviewed review)
- Transvaginal Ultrasound — Cleveland Clinic