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Okay, so our first lesson is

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Müllerian duct abnormalities,

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so we'll have to go all the way back to

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embryology, which is everyone's favorite topic.

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So, during embryology, you have

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paired embryologic structures,

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which are the Müllerian ducts.

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You have development, you have fusion, and

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then you have resorption, all occurring in

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utero at approximately the 6 to 11 week mark.

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And this forms the uterus, the

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fallopian tubes, the cervix, and the

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proximal two-thirds of the vagina.

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And that's important because that's what

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you're going to see when errors occur.

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That's going to result in your Müllerian duct

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abnormalities in those specific structures.

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So that's what you'll need to look for.

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So, interruption of these events, these result

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in the MDAs, the Müllerian Duct Anomalies.

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They can be associated with renal anomalies,

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remember the GU system, but they are

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not associated with ovarian anomalies.

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That's a different system

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there with how these form.

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So why are these important?

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It's important because 15 percent of patients

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who have repeated miscarriages end up having

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an MDA and that can be either fixed or

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counseled to figure out what you can do next.

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So in general, if you think

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you're up against an M.

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D.

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A.

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and trying to figure out what exactly it

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is that you're seeing to help guide the

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surgeon or the OBGYN about what to do next.

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You always consider the number

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of horns that are present.

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Is it one or is it two?

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And then the spacing of those horns.

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Are they together?

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Are they widely divergent?

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You want to note how many cervixes there are.

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Are there one or are there two?

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And then the fundal contour of the uterus.

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Is it flat?

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Is it concave?

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Is it convex, or how much so?

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And that's going to help you decide what it

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is that you're looking at and help with surgical

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planning if it's a surgical type of case.

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So different types.

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We have the agenesis on one side where different

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parts of the Müllerian ducts don't form at all.

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And then you have the arcuate uterus.

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That one is a little bit tricky, whether that's

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actually an anomaly or not, or just a border

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of a normal variant, particularly right there.

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We'll talk about that a little bit more later.

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The rest of these are going to be

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either fusion problems or they're

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going to be resorption problems.

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And that's a good way to think of it when

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you're trying to figure out what's going on.

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I will note that this list is not inclusive.

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For example, a lot of this stuff

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is going to be on a spectrum.

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Even just starting with agenesis, you can have

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varying degrees of hypoplasia or agenesis.

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Something may not fit particularly

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into a single category.

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And if that's what you find that you have

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in front of you at that particular time,

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the best thing to do is just describe it

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for that surgeon to be able to figure out what

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they're seeing, if they're going to take them

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to the operating room and to best counsel them.

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Overall, it's estimated about 5

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percent of women will have an M.

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D.

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A.

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There are differing reports, though,

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as to what the most common is.

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But most people think that it's likely

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the septate uterus that is most common.

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Jumping back to that argument, that's

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an incomplete resorption problem.

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The two ducts fuse together, but then the wall

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in between them doesn't completely resorb,

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but it results in a near-normal appearance and

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usually does not have an effect on fertility.

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Generally, you don't get surgery for

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these or anything to correct them.

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But if you have repeated pregnancy loss

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without any other imaging factors, they

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may consider it on a case-by-case basis.

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It's also important to know that you're usually

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going to start these on ultrasound due to

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the presenting symptoms and the availability.

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So these may be a little bit difficult

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to talk about the contour of the uterus,

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which is one of the important things,

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but with the availability of 3D, you're

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really going to need to rely on that.

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However, if it's complex or it's unclear

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and you're not sure what's going on, MRI

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is the gold standard of imaging for this,

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but you do need a very specific protocol.

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So it is important to keep in mind

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you'll need a small T2 field of view.

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And again, we'll go over these in a little bit.

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You need a plane to lay out the uterus

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as much as possible so that you can

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measure a septum if it's present.

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So the surgeon knows what they

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are going to see and how much they

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may need to potentially operate.

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And then you need to appreciate that

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frontal contour, which is why you need

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the uterus to lay out in one single plane.

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You also need T1 to look for retained

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blood products, and you should get

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a view of the kidneys as well to

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look for any associated anomalies.

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And you can do that via MRI or ultrasound.

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In general, about 30 to 50 percent

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of these will have a renal anomaly.

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The most common is unilateral agenesis,

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but you can also see things such as atresia,

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hypoplasia, fusion, malrotation, and duplication.