What to Expect in an Egg Freezing Ultrasound

If you’re thinking about freezing your eggs—or you’ve already signed up—the word “ultrasound” will come up a lot. In fact, it’s one of the most common touchpoints during the egg freezing process. But if your only reference point is a pregnancy ultrasound you’ve seen on TV or in a friend’s baby announcement, this might feel like uncharted territory.

Egg freezing ultrasounds look a little different than the ones used during pregnancy. For one, they’re internal (more on that in a bit). And they aren’t just for a one-time peek. These scans play an important role before, during, and after your egg freezing cycle. Whether you're considering our Split program and freezing your eggs for free when you donate half the eggs retrieved to intended parents that can't otherwise concieve, or our Keep program, it’s helpful to understand how ultrasounds fit into the experience.

This article walks through the different types of ultrasounds you may have during the egg freezing process, what each one is looking for, and what to expect physically and emotionally. We'll also touch on timing, frequency, and how to prepare, so nothing catches you off guard.

Types of ultrasounds used in egg freezing

Egg freezing relies on transvaginal ultrasounds to assess your ovaries and monitor your response to medication. While the phrase “transvaginal ultrasound” might sound a little intimidating, it’s a routine procedure that fertility clinics perform multiple times a day.

Here’s a breakdown of what that means:

• Transvaginal means the ultrasound probe is inserted into the vagina, allowing the provider to get a closer, clearer image of your reproductive organs than an abdominal ultrasound would allow.
• Ultrasound refers to the use of high-frequency sound waves to create images of internal structures—in this case, your ovaries and follicles (fluid-filled sacs that may contain eggs).

If you’re used to pelvic exams or have had a pap smear, the experience is generally comparable—sometimes even quicker and more comfortable. The probe is typically covered with a condom and gel, and the entire scan usually takes less than 10 minutes.

When and why you’ll have ultrasounds

Egg freezing involves a series of ultrasounds at different points in your cycle, each one with a specific purpose. Here's how they typically line up:

1. Baseline ultrasound (before you start medications)

This scan is usually done early in your menstrual cycle, often on day 2 or 3 of your period. It's designed to assess your ovaries in their resting state—before any stimulation begins.

Your provider will check:

• How many antral follicles (small follicles visible at baseline) are present in each ovary
• The size and appearance of your ovaries
• Whether there are any ovarian cysts or abnormalities

This is also when your provider may confirm your AFC (antral follicle count), which, along with bloodwork like AMH levels, helps estimate how your body might respond to medication.

2. Monitoring ultrasounds (during stimulation)

‍Once you start injecting hormones to stimulate your ovaries, you’ll likely have several monitoring ultrasounds (typically every other day or so) for about 8–12 days. These scans help your provider track:

• How many follicles are growing
• How quickly they’re maturing
• Whether both ovaries are responding equally
• Whether any adjustments to your medication dose are needed

During this phase, your medication protocol might be tweaked in real time to help mature as many eggs as possible while keeping safety top of mind. These ultrasounds are usually paired with bloodwork to check your estrogen levels.

3. Trigger day ultrasound (right before retrieval)

The final monitoring ultrasound will determine when you’re ready to take your “trigger shot,” which pushes the final maturation of your eggs. Timing is everything here—the retrieval needs to happen around 36 hours after the trigger, before ovulation would naturally occur.

In this scan, your provider is looking for:

• Follicles that are large enough (usually around 17–20 mm in diameter)
• Signs that your ovaries are responding well to stimulation
• Whether you’re ready for retrieval the next day or need one more day of medication

What the ultrasound actually feels like

Physically, a transvaginal ultrasound is more awkward than painful. You’ll be asked to undress from the waist down, lie back on an exam table with your feet in stirrups, and try to relax your pelvic muscles while the probe is gently inserted. The provider will usually talk you through what they’re seeing on the screen. If an ultrasound technician is doing the scan, they may not talk you through things but the provider will review everything with you afterwards.

The probe itself (which some people in the fertility community affectionately call “Wanda”) is a little wider than a tampon and doesn’t go in very far—just enough to visualize your uterus and ovaries. Once it’s in, the provider may move it slightly to get different angles. You might feel some pressure, especially if your ovaries are enlarged from stimulation meds, but the discomfort is typically short-lived.

It’s okay to ask your provider to go slowly or pause if you’re feeling uncomfortable. If you’re prone to anxiety during pelvic exams, letting the clinic know ahead of time can help them tailor the experience for you.

What they’re measuring (and why it matters)

During each scan, your provider is tracking the size and number of follicles in each ovary. These follicles are where your eggs grow, and not every follicle will necessarily contain a mature egg—but it’s the best visible marker they have to guide the process.

They’ll measure each follicle’s diameter in millimeters, usually noting the count of follicles in different size ranges. For example, follicles over 14mm are more likely to contain a mature egg, but some clinics wait until they reach 18–20mm before triggering.

This information helps guide:

• Whether your meds are working as expected
• When to adjust doses (up or down)
• When to schedule your egg retrieval

The goal isn’t to get the most eggs possible at all costs—it’s to get a healthy number of mature eggs while minimizing risks like ovarian hyperstimulation syndrome (OHSS). Ultrasound monitoring is what makes that possible.

How many ultrasounds should you expect?

While protocols can vary based on your clinic and your individual response, here’s a rough estimate of how many scans are typically involved:

• 1 baseline ultrasound
• 3–5 monitoring ultrasounds during stimulation
• 1 final ultrasound before the trigger shot

So in total, you’re probably looking at 5–7 ultrasounds over the course of your egg freezing cycle. Most clinics will schedule these in the mornings to give you time to get to work or class afterward, but it’s a good idea to build in flexibility that week.

Can you do ultrasounds at a local clinic if you don’t live near your provider?

Yes—many egg freezing programs, including Cofertility, can work with monitoring partners near you if you’re not close to the fertility clinic doing your retrieval. You’d do your baseline and monitoring scans at a local clinic, and then travel to the retrieval clinic for the final stages.

This kind of remote coordination requires clear communication between the two clinics, especially when it comes to sending ultrasound results quickly. Your cycle coordinator will usually help with the logistics so you’re not left chasing down images and reports.

Tips for getting through ultrasound week

• Wear easy-on, easy-off clothes. A comfortable dress or loose pants can make it quicker to change for the scan.
• Schedule smart. If your clinic offers early morning appointments, take advantage—it helps you get in and out faster and limits time away from other responsibilities.
• Ask questions. Don’t be shy about asking what the provider sees on the screen or how your response compares to what’s expected.
• Take care of yourself. Your ovaries can feel a little bloated or tender as follicles grow. Hydrate, take it easy, and skip high-impact workouts until after retrieval.

The bottom line

Ultrasounds are a big part of the egg freezing process, offering real-time feedback about how your body is responding and helping your care team make the best decisions for your cycle. While the idea of multiple transvaginal scans might sound intimidating at first, most people find that the visits become pretty routine—and even reassuring—as the cycle progresses.

Knowing what to expect can make the whole experience feel a lot less mysterious. And remember: if something feels confusing or uncomfortable, you’re always allowed to speak up. You’re the one in the stirrups, after all.

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