Ultrasound Assessment for Fertility - By Dr. Alex Hartman (Summer 2010)

ULTRASOUND ASSESSMENT FOR FERTILITY
What your ultrasounds can tell you

Dr. Alex Hartman

Summer 2010

Ultrasound seems to be everywhere you turn these days, and even more so once you decide to try starting a family.

So what exactly is ultrasound? Ultrasound simply refers to high frequency sound waves. Diagnostic ultrasound uses thin beams of sound, which are sent from an ultrasound transducer (probe) into the body. Some of these waves bounce back and create a picture. (My apologies to any of you who are physicists. This is the only way I... or just about anyone else... can understand the concept.)

Why use ultrasound? When properly performed, ultrasound is safe, reliable, inexpensive and portable. You don't need to worry about radiation, allergic reactions, anaesthetics, or even delays in interpretation.

Ultrasound is the most important imaging modality used in creating families. This article will show how and why ultrasound is used for investigation in reproductive medicine. The different types and uses of ultrasound will be explained.

Your ultrasound examination

While you are clearly the star of your procedure, your co-stars include the ultrasound machine, the person scanning and the interpreter of the scans.

You can't tell the quality of an ultrasound machine by looking at it. They come in all shapes and sizes. A big, impressive-looking machine may give terrible images, while a small model may be state of the art. In general, new machinery gives much better resolution, or clarity. Modern machines are also better equipped to zoom in and measure areas of interest. Most machines also have Doppler capability, which means that the user can check blood flow. Later, we will discuss 3-D ultrasound, which may also be used to evaluate the uterus, fallopian tubes and ovaries.

While some people get scanned by their doctors, most patients are scanned by sonographers. Here are two things you need to know about your sonographer: first of all, she is a well-trained professional, who is trying her best to do her job. Second, she is terrified that her scanning will cause you discomfort. Sometimes she is so worried that she forgets to smile. I know that as patients, we can get nervous when we are scanned, but it may help to know that the sonographer’s main job is to do no harm. If she forgets to say good morning to you first, consider getting the ball rolling yourself.

The person interpreting may be the doctor who scans or someone reviewing the procedure afterwards. Many people ask the sonographer for results and are upset when they don't get answers. Sonographers are generally not permitted to give patients the diagnosis. Provincial regulatory bodies do not allow it. Your doctor may have also left orders not to give results to patients. So don't become nervous if the sonographer sighs during the scan, or grimaces. It may just be last night's enchiladas.

Initial assessment

Your first reproductive ultrasound may occur even prior to your first appointment with the doctor. The scheduling is done slightly differently depending on your doctor's preferences and the availability of resources.

Most people have their initial scan early in the cycle. Many centres will do a transabdominal, or "full bladder" study. This isn't done to punish you, we promise. Scanning over your lower abdomen allows for a wider view of what's going on in the pelvis. We use the bladder as a window to help us look. Of course, the bladder doesn't have to be so full that you are in pain.

Prior to your transvaginal scan you will be asked to empty your bladder. This allows for better visualization of the uterus. The ultrasound probe, also called the transducer, is a long slender wand that is introduced just a few centimetres into the vagina. Prior to insertion, the probe is bathed in a cleanser, wrapped in a condom, and covered with gel. This is done for safety and comfort. The sonographer will only insert the probe as much as is required. Definitely give her feedback if it is pinching.

The uterus

The first structure usually imaged is the uterus. Most are pointed forward, which is referred to as anteverted, but 15 percent of women have a uterus that is pointed backwards, or retroverted. It was formerly believed that a retroverted uterus was a risk factor for infertility, but that's not the case. The uterus is relatively small, measuring about 5 centimetres in size. We also view the uterus to ensure the texture is normal. We want to make sure there are no fibroids (noncancerous tumours on the uterus). We view the lining to see the thickness and homogeneity.

Normal anteverted uterus. The bright area on the left is the endometrium, which becomes thicker and brighter due to progesterone.

There are many findings that we commonly visualize in a uterine ultrasound. Some of these can potentially affect your ability to have a baby. We also view your cervix, which connects the uterus to the vagina. We mainly look at its length and make sure it looks adequate to carry a baby.

The endometrium, or uterine lining

With menstruation the lining sheds, so early in each cycle the lining is thin. It starts to thicken up due to estrogen, but stays relatively hypoechoic – meaning that it is fairly dark and does not reflect a lot of the sound waves on ultrasound. In the secretory phase, or after ovulation, progesterone causes further thickening of the lining and the lining becomes brighter. Since your uterine lining can reflect your hormone status, this is another way to tell how receptive your uterus is to welcoming and nurturing a fertilized egg.

Uterine size

A tiny uterus may be due to failure to develop or to a severe hormone imbalance. These are very uncommon. What is much more common is a large uterus. A woman's uterus is usually larger after she has had children. We measure the size and carefully see if there are any focal abnormalities. The most common abnormalities are fibroids.

Fibroids

Fibroids are growths of uterine muscle tissue that start from a single cell. They can be any size and are seen in about half of all women. They can cause bleeding and contribute to infertility. The good news is that most fibroids don't cause problems. How can we tell if they will cause trouble? Think of fibroids like you think about real estate: location is everything.
In general, fibroids are important if they indent the inner lining of the uterus. Only about 5 percent of women have these. Most other fibroids are not important unless they are very large.

This fibroid is completely within the uterine cavity on this sonohysterogram of this patient with abnormal bleeding.

Polyps

Endometrial polyps, or polyps in the lining of the uterus, are seen in thirteen percent of women trying to have a child. They are growths of the lining cells and look like skin tags. Polyps can cause bleeding and theoretically can act like an IUD and prevent pregnancy. There is still some controversy about polyps' influence on infertility. However, most doctors suggest removing polyps larger than 1 centimetre.

Large polyp seen on a sonohysterogram. The blue and red represent blood flow. There is a large artery going through the centre of the polyp.

3D Ultrasound

If an ultrasound is a thin beam of sound, then 3D ultrasound refers to hundreds of adjacent beams that create a box (or volume) of data. When we think of 3D ultrasound, most of us imagine those beautiful images of second and third trimester foetuses. There is an important use for 3D ultrasound in the fertility investigation as well. Canadian research has shown that approximately 30 percent of women trying to conceive have a uterine malformation or a variation in the shape of the uterus. Most of these don’t cause problems. However, some of these are associated with difficulties in conceiving and with miscarriage. Having a 3D ultrasound is especially important if there is a history of miscarriages.

Sonohysterography

This is another area where Canadian research has been at the forefront. Sonohysterography is a procedure where a tiny tube is placed in the cervix and about a teaspoon of salt water is instilled. The procedure gives us an enormous amount of information about the uterine cavity, including the best ultrasound assessment of polyps, fibroids, scarring and endometrial thickening.

The procedure can be easy when performed by an experienced physician. Having personally performed more than 75,000 sonohysterography procedures, I can honestly say that you may feel very little and the whole test is usually over in a couple of minutes. The patients, sonographers and I often tell jokes throughout. This examination is often combined with 3D ultrasound to look for uterine malformations.

I tell all patients to take an anti-inflammatory, such as ibuprofen, prior to a sonohysterogram. It’s not because of discomfort, but because it helps open up the fallopian tubes. Some centres pre-treat with antibiotics as well.

Ultrasound tubal patency analysis

In terms of medical technology, 100 years is a long time.

The first X-RAY dye tubal patency study (hysterosalpingogram) was performed in 1910. There have been few changes since in how this procedure has been conducted. The test is uncomfortable and exposes you to radiation and possible reaction to the dye. Many centres have followed our lead and no longer use this X-RAY procedure to screen for patency of the fallopian tubes.

So what do many experts use? Remember that a sonohysterogram uses a tiny catheter to instill fluid. After checking the uterus, why not put in a special sugar solution, or salt water, to assess the tubes? The catheter is already in the right place. Why not try and see if you can see if the tubes are open by the simple means of checking whether the water solution inserted into the tubes passes out the other end? The Canadian Fertility and Andrology Society (CFAS) and the American Society for Reproductive Medicine (ASRM) both promote the use of ultrasound for tubal patency. Unfortunately, like sonohysterography, to achieve a level of expertise with this procedure requires a great deal of practice.

We are trying to see whether one or both tubes are open. Tubal blockage is a factor in 25-40 percent of couples with infertility. We are especially concerned if you have a history of endometriosis, pelvic inflammatory disease (PID), or an ectopic pregnancy. We are also on the lookout for non-functioning fluid-filled tubes, called hydrosalpinges, which can decrease your chance of pregnancy unless they are dealt with.

Ovaries

Your ovaries are the site of egg maturation. Ovarian appearance also often reflects hormone status. We carefully measure the size of the ovaries, since up to half of all patients who visit a fertility specialist have polycystic ovaries. This refers to having large ovaries and/or lots of tiny follicles (tiny cysts where the eggs grow) early in the cycle. This can be normal for you, but becomes important if associated with infrequent menstrual cycles and signs of too much male hormone (lots of hair growth, etc).

We commonly see cysts in the ovaries (which look like black bubbles on the screen). Most are functional (not disease-related) and disappear on their own, usually within 2 months. These are more commonly seen if you have been given medications, such as clomiphene. Other cysts are complicated. That means they are not just thin-walled and contain clear fluid. These include corpus luteum cysts which are normal. “Chocolate cysts” are due to endometriosis, are blood filled and can be a cause of pain and blocked tubes. We also look for any other abnormality of the ovaries, such as dermoid cysts.

Follicular monitoring

A group of follicles are expected to grow during the cycle. Your doctor will usually use ultrasound as a means to watch the follicles ripen. The ripening follicles produce increased quantities of estrogen, which causes the endometrium to thicken and change its appearance. We hope to see a thickened lining with an appropriate appearance, such as a triple-layered look.

Combining ultrasound examinations with an assessment of hormone levels can help your doctors know how many eggs are growing and if there is consistency between the ultrasound and hormone measures. There are usually more follicles to be seen growing during a stimulated cycle compared to a natural one. Ultrasound is also used to detect ovulation, if it occurs naturally. In other cycles, the sizes of the follicles (usually over 1.5 cm) as well as estrogen levels help determine when to intervene and bring about ovulation.

In summary, ultrasound is a valuable tool that is becoming ever more important in our investigation of issues regarding fertility. It is a comfortable, safe, reliable, portable and inexpensive method to obtain information. This article has concentrated on the ultrasound’s uses as a diagnostic tool. Many of these techniques are new, based on research performed in Canada. There are also many uses for ultrasound in the treatment of infertility. Whether used for investigation or treatment, ultrasound has proven to be extremely valuable in creating families.

About the Author
Dr. Alex Hartman is the Director of Imaging at True North Imaging and at six fertility clinics in the Toronto area. Dr. Hartman is also the Chair of the Imaging sections of both the Canadian Fertility and Andrology Society and the American Society for Reproductive Medicine. You can reach Dr. Hartman at: ahartman@truenorthimaging.com or view True North’s website: www.truenorthimaging.com