The Baseline Ultrasound in IVF: What is It & Why Do You Need It

Are you starting an in vitro fertilization (IVF) cycle and have a baseline ultrasound scheduled?

In this article, you will learn:

  • What is a baseline ultrasound
  • When in an IVF cycle is it performed and why
  • What to expect at the scan and more

Let’s get started.

ivf baseline ultrasounds cover image

What is a baseline ultrasound in IVF?

A baseline ultrasound is a scan done early in your menstrual cycle before starting any fertility medications.

The goal of this scan is to check how many antral follicles you have in each ovary and to ensure there are no abnormalities in your uterine cavity, endometrial lining, or ovaries.

This ultrasound examination also gives us a sonographic “baseline” for future ultrasounds.

What happens during the scan?

You will first be brought into the exam room and asked to confirm your name and your date of birth. The ultrasound technician will then step out and ask you to undress from the waist down and provide you with a sheet to drape yourself for privacy.

The sonographer or physician will then enter the room with a chaperone and introduce themselves. After that, they will ask you to slide down the examination table and place your feet into the footrests.

The person performing the ultrasound will then place a small amount of gel on the ultrasound probe before introducing the probe vaginally.

After introducing the probe, they will check both ovaries for size, the number of antral follicles within each ovary, the size and shape of the uterus, and the uterine lining thickness.

The entire ultrasound will take about 5 minutes, and the person performing it will walk you through every step.

After the scan, you will have a blood test to check your baseline hormone levels.

Is A baseline ultrasound painful?

The baseline ultrasound scan is not painful, but it can be uncomfortable. You may feel some pressure when the probe is first introduced, but any discomfort tends to go away fairly quickly.

In addition, the person performing the ultrasound will go into great detail about every step of the process and walk you through what to expect.

When is It done for IVF?

The baseline ultrasound is done on or around days 2-5 of your menstrual cycle.

The day that you begin bleeding (full flow) is considered day 1.

picture of a calendar saying: most fertility treatments start on Day 3-5 of your cycle

If your full flow starts in the evening, cycle day 1 is the following day. (Be sure to check with your clinic what specific time corresponds to day 1 versus day 0).

If you do not have regular menstrual cycles, the baseline scan can also be done on a random day of your cycle.

Is it normal to have A Baseline Scan during my period?

Yes, the baseline ultrasound is performed on ~cycle day 3 of your period, so it is perfectly normal to still be menstruating.

Do not be embarrassed!

All patients undergoing fertility treatment will have a scan done during a period.

How many follicles should you have at The baseline ultrasound? What is a good number?

In general, we like to see roughly 6-8 follicles on each ovary, but there is a lot of variety among patients, and this number naturally falls as you age.

A high number of antral follicles at baseline often correlates with the number of follicles that will develop during stimulation.

In addition, the lower your anti-mullerian hormone level (a marker of ovarian reserve), the lower your antral follicle count will be.

ultrasound image of an ovary showing many antral follicles

With that said, it is important to note that quantity isn’t the only factor. The quality of eggs and sperm is important too.

Unfortunately, we do not have any methods of assessing egg quality and how it can contribute to infertility.

How many ultrasounds do you have during An IVF Cycle?

In general, you can expect to have between 4-6 ultrasounds during your IVF cycle.

The first ultrasound is a baseline scan done on menstrual cycle day 3. You will then return to the office after approximately 3 days of your ovarian stimulation injections.

The purpose of these follow-up visits is to check your follicular development and hormone levels.

Depending on how quickly your follicles grow, you will return every 1-2 days until you are ready to trigger.

What Does A Typical IVF Ultrasound Schedule Look Like?

Below is a typical timeline of what you might expect from your IVF monitoring schedule.

  • Day 1: First Day of Your Menstrual Period (Full Flow)
  • Day 3: Baseline Ultrasound, Start of Gonadotropin Injections
  • Day 6: Ultrasound Monitoring Visit
  • Day 8: Ultrasound Monitoring Visit
  • Day 10: Ultrasound Monitoring Visit
  • Day 11: Ultrasound Monitoring Visit
  • Day 12: Ultrasound Monitoring Visit – Trigger Shot (HCG or Lupron or Both)
  • Day 14: Egg Retrieval

I go over this in more detail in The IVF Timeline: How Long Is The IVF Process From Start To Finish.

I had a cyst on my IVF baseline ultrasound. Is this normal?

Ovarian cysts are not unusual at the baseline scan.

The vast majority are benign and often are leftover follicles from your previous menstrual cycle.

Often, small cysts can resolve on their own, but others may persist.

The first step is to check your estrogen level on bloodwork. If your estrogen/estradiol levels are elevated (>60-80 pg/mL), it is best not to start the IVF cycle this month.

Your reproductive endocrinologist may prescribe medication such as birth control pills to help prevent the cyst from growing, which can help resolve the cyst.

Suppose you do not have an elevated estradiol level, and the cyst is not excessively large. In that case, your fertility specialist will likely allow you to start the stimulation.

Either way, it is essential to follow up with your doctor closely if your cysts persist after the IVF treatment cycle.

Is a baseline ultrasound for IUI different?

The baseline ultrasound for an intrauterine insemination (IUI) is the same as a baseline scan for an IVF cycle.

The ultrasound is still done on cycle day 2-3 of your menstrual cycle and will help determine if you can start your IUI cycle that day.

Unlike IVF, an IUI cycle typically use oral ovulation induction medications (like Clomid or Letrozole).

In addition, you should not expect to need as many ultrasounds during an IUI cycle as you would in an IVF cycle.

Read my post on IVF vs IUI to learn more.

What About For A frozen embryo transfer cycle?

A baseline scan is also done at the beginning of a frozen embryo transfer (FET) cycle.

The key difference is that we are primarily focusing on the endometrial lining and not your antral follicles.

If you choose to do a medicated FET, we don’t want any ovarian follicles to grow.

If you choose to do a natural cycle, our goal is to grow one follicle.

I go over all the details in my post on Frozen Embryo Transfers.

Final Words

The baseline ultrasound is the essential first step in any IVF treatment plan. This transvaginal ultrasound helps to determine:

Together with blood work, the information provided from the scan will help optimize your cycle and increase your chance of success.

To learn about the next step, check out these articles:

Make An Appointment With Dr. Robles To Discuss Your Fertility Options Today!

alex robles

Alex Robles, MD

Dr. Alex Robles is a Spanish-speaking Latino-American Reproductive Endocrinologist and Infertility specialist in New York City, and a board-certified OBGYN. He has a special interest in health, lifestyle, & nutrition. Make an appointment with Dr. Robles to discuss your fertility options today!

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