Starting your IUI treatment could be a great and stressful experience at the same time, particularly if you have to manage all the tests and appointments with your doctors.
The baseline ultrasound is the initial and essential step to determine the right treatment for you. This scan provides your doctor with a clear picture of your body's natural cycle.
What is a baseline ultrasound?
A baseline ultrasound is the first important scan you’ll have when beginning an intrauterine insemination (IUI) treatment cycle.
Your doctor will schedule this ultrasound early in your menstrual cycle, usually on days 2, 3, or 4, before any medications begin.
The timing matters because it gives your doctor a clear view of your reproductive system in its natural, resting state. This helps guide the next steps of your treatment plan.
Why is it important?
This scan offers helpful insight into how your body is doing before stimulation begins. It allows your doctor to:
Count the number of small resting follicles (called antral follicles) in your ovaries—these are the ones that could grow with medication
Check for ovarian cysts or anything else that might affect your treatment.
Measure the thickness of your uterine lining to ensure it’s ready for possible implantation.
Look for fibroids, polyps, or unusual shapes in the uterus that may need attention.
This information helps your doctor decide if it’s safe to start medications like Clomid, Letrozole, or injections and gives a good idea of how your ovaries might respond during the cycle.
When and why is a baseline ultrasound performed?
Timing your scan
Your baseline ultrasound is scheduled very early in your menstrual cycle, typically between day 2 and day 4. Day 1 is counted as the first full day of your menstrual bleeding.
This early timing is chosen carefully because it's when your ovaries are in their most natural, resting state. This gives your doctor the clearest starting picture before any treatments begin.
Why does your doctor schedule the ultrasound scan?
Start of treatment planning:
It helps your doctor decide if your body is ready to begin ovarian stimulation medications.
Rule out cysts:
Detecting ovarian cysts is important, as their presence may mean your ovary is already hormonally active and treatment should be postponed.
Establish a baseline:
This scan serves as a reference point so your doctor can monitor how your follicles grow during the cycle.
For more information about your fertility journey and to receive advice tailored to your unique situation, consider speaking with a fertility specialist. You may contact Thomson Medical to arrange a consultation for personalised guidance on baseline ultrasounds, treatment options, and the next steps in your path to pregnancy.
What preparations are needed for your baseline ultrasound?
You don’t need to do much to get ready for the scan, but a few simple steps can help things go smoothly. Here’s what to keep in mind:
No need to fast—you can eat and drink as usual
Try to empty your bladder just before the scan (this helps with clearer imaging during a transvaginal ultrasound)
Wear comfortable clothing that’s easy to change in and out of
Bring a list of any medications you’re currently taking
Let your doctor know if you’ve had:
Any pelvic pain, surgeries, or infections
Previous fertility treatments or cycles
You won’t need any sedatives or anaesthesia, as this is a quick and straightforward outpatient procedure.
What to expect during the scan?
Knowing what happens during the scan can help you feel more at ease. Here’s a quick step-by-step of what you can expect:
You will be required to wear a medical gown and lie on the examination table with your feet gently placed in stirrups.
A transvaginal ultrasound probe (an object about the size of a tampon) will be softly inserted into your vagina.
The probe uses sound waves to create images of your uterus, ovaries, and endometrial lining on a screen.
The entire scan usually takes around 5 to 15 minutes.
Your doctor may take measurements and save images for your medical records.
It is not painful, but you may feel a little discomfort if you have cramps due to your period.
What do your baseline ultrasound results mean?
Before a doctor goes over the plan for the next IUI cycle, there are a few things to look at after the scan:
Ovarian reserve:
This refers to the number of small resting follicles (called antral follicles) in each ovary.
Normal: 8 to 15 follicles per ovary
Low: Fewer than 5 follicles per ovary
More follicles usually mean your ovaries may respond better to fertility medications.
Cysts:
They are fluid-filled sacs that sometimes appear on the ovaries. If there are some present, then the cycle may be delayed as they signal hormonal activity.
Endometrial lining:
At baseline, the endometrium lining should be thin and about 3 to 6 mm. A thicker lining at this point in time can be considered an indication of a hormonal imbalance, which must be corrected before continuing with the process.
Uterus:
The scan also provides a check on the condition of the uterus’ shape and size, and at the same time, it looks for any abnormalities like fibroids or polyps that could make implantation difficult.
Your doctor will walk you through the results and let you know whether it’s safe to begin medication or if any adjustments are needed before proceeding.
Are there any risks with a baseline ultrasound?
Baseline ultrasounds are very safe and are a routine part of fertility care. There are no major issues that usually come up, but here is a list of what you could experience:
During the scan, you might feel mild cramping or discomfort.
Slight vaginal irritation or light spotting may occur after the scan
Infection is extremely rare, but your doctor will always take precautions to keep things safe and sterile
If you experience any unusual symptoms or pain after the procedure, do not hesitate to contact your clinic. It is always advisable to ask and be sure of your condition.
FAQ
Is a baseline ultrasound painful?
Most people don’t find it painful, but you might feel some mild discomfort. The ultrasound probe is smaller than the speculum used for a Pap smear, so it’s usually pretty manageable.
Can a baseline ultrasound detect pregnancy?
A baseline ultrasound examination cannot detect pregnancy because it is done too early in your menstrual cycle. Ultrasound can perform pregnancy tests after approximately 5 to 6 weeks of gestation, but your baseline scan occurs much earlier.
How many ultrasounds will I need for IUI?
You’ll typically have 2 to 4 scans per cycle:
One baseline scan at the start
One or more mid-cycle scans to track follicle growth
A scan to check ovulation timing when your follicle is mature
If you’re taking fertility medications, you may need more frequent scans to monitor your response and avoid overstimulation.
What’s a normal follicle count in a baseline ultrasound?
Your doctor will check for small resting follicles (antral follicles) in each ovary:
Normal range: 8–15 per ovary
Low ovarian reserve: Fewer than 5
High count: Over 20, which could point to PCOS
At baseline, there shouldn’t be any dominant follicles (over 10 mm) or active cysts.
How is a baseline ultrasound done?
The baseline ultrasound scan uses a transvaginal approach, which means the ultrasound probe is gently placed inside your vagina. This method gives your doctor the clearest, most detailed images of your ovaries, uterus, and endometrium lining. While it might sound intimidating, most women find it similar to a routine pelvic organ exam.
How can I increase my chances of IUI success?
Monitor ovulation closely with scans and bloodwork
Use a trigger shot (hCG) if recommended to time the IUI
Take prescribed ovulation stimulants if advised
Keep a healthy BMI
Avoid smoking, limit alcohol, and cut back on caffeine
Address any male fertility factors (like sperm quality)
Try stress reduction techniques, such as acupuncture
Multiple cycles improve success rates, so don't give up if the first attempt doesn't work.
The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations based on your medical conditions, request an appointment with Thomson Medical.