Heart-shaped uterus: causes, effects and what it means for you

What is a heart-shaped uterus?

Maybe you heard the term for the first time during an ultrasound, almost in passing, and a thousand questions have been running through your head ever since. That is completely understandable. A diagnosis about your uterus can quickly feel threatening, especially if you want to have children. So here is the most important thing first: a heart-shaped uterus is not a disease, it is a variation in shape that the vast majority of people live with just fine.

Normally the uterus is smooth and slightly domed at the top. In a heart-shaped uterus the upper part, the so-called fundus, is pulled inward. This dip splits the upper area into two bulges that look a little like the two curves of a heart. Doctors then usually speak of a bicornuate uterus, literally a two-horned uterus.

These congenital shape variations are more common than many people think. A bicornuate uterus occurs in about 0.4 percent of all women, roughly four in a thousand. The mildest form, the arcuate uterus, is even more common and is generally considered a normal variant with no disease value.

How does a heart-shaped uterus develop?

The shape forms long before you are born, back in the womb. In the first weeks of pregnancy the uterus grows together from two narrow ducts, the so-called Muellerian ducts. Normally these two ducts fuse completely into a single, pear-shaped cavity.

In a heart-shaped uterus the two ducts fuse only partially. A dip remains at the top, and that is exactly what gives the uterus its heart shape. It simply happens during development. You did nothing wrong, and it has nothing to do with your lifestyle. Nobody gets a heart-shaped uterus because she moved too little or ate the wrong things.

One thing is good to know: because the uterus and the kidneys develop at the same time in the womb, up to 30 percent of those affected also have the kidneys involved, for example a missing or differently formed kidney. That is why your doctor often also looks at the kidneys during the work-up. This is routine, not a reason to panic.

Heart-shaped, arcuate or bicornuate: what is the difference?

The terms get mixed up, so here is a short overview. Congenital shape variations of the uterus form a spectrum, from very mild to pronounced:

• Arcuate uterus: the mildest form, just a shallow dip. Usually considered a normal variant with no consequences.
• Bicornuate uterus: the classic heart shape with a clear indentation and two bulges. This is what people mean when they talk about a heart-shaped uterus.
• Septate uterus: here a wall of tissue divides the inside, while the uterus is smooth on the outside. This form carries the highest risk of miscarriage and is the one most likely to be treated.

Where exactly the line between arcuate and bicornuate lies is something doctors decide based on the depth of the indentation. As a rule of thumb: if the dip is deeper than about 10 millimetres, it is called a bicornuate uterus; if it is shallower, more likely an arcuate one. For you this mainly means: heart-shaped is not always the same, and the exact form helps decide whether there is anything to watch at all.

What symptoms does a heart-shaped uterus cause?

For most people: none at all. Many find out about their heart shape only by chance, for example during an ultrasound in pregnancy or while looking into something else.

If there are symptoms, they are most likely these:

• Heavier or longer bleeding, because there can be more lining in the upper area.
• Stronger period pain than you were used to.

Important here: if your bleeding is very heavy or your period pain regularly knocks you out of everyday life, that is not something you simply have to put up with. Such symptoms deserve a closer look, quite apart from the shape of your uterus. Raise them at your practice so you can look together at what is behind them and what helps.

Can I get pregnant with a heart-shaped uterus?

For many people this is the real question, and the good news is: in the vast majority of cases, yes. A heart-shaped uterus does not usually make it harder to conceive in itself. Ovulation, egg maturation and fertilisation happen independently of the external shape of the uterus.

Shape variations of the uterus are somewhat more common among people with an unfulfilled wish to have children than in the general population. But that does not mean the heart shape is automatically the cause. Very many people with a heart-shaped uterus get pregnant without help and have healthy children. So such a diagnosis is not a verdict on your family planning.

If you want children and pregnancy is taking a while, raise it early at your practice or at a fertility centre. Together you can clarify whether the shape plays any role or whether other factors matter more.

What effects does it have on pregnancy?

Here an honest but calm assessment helps. In pregnancy a heart-shaped uterus does come with a somewhat higher risk of certain complications, mainly with a bicornuate and a septate uterus. With the mild arcuate form there is usually no relevant effect to expect.

These points are seen more often in studies:

• Miscarriages in the first and second trimester occur somewhat more often.
• Preterm births are more likely, in studies in roughly one in five pregnancies.
• The baby's position is more often breech or transverse, because there is less room at the top. This more often leads to a planned caesarean.

As matter-of-fact as this list sounds, the other side matters just as much: many people with a heart-shaped uterus carry their baby without major problems. Your pregnancy is then simply monitored a little more closely, so that any issues can be caught early. This is not doom and gloom, it is care. If you are pregnant or want to be, your gynaecologist is the right person to assess your very personal situation.

How is a heart-shaped uterus diagnosed?

Often it is an incidental finding. The indentation shows up on an ultrasound, and suddenly the term is in the room. For a precise diagnosis, and above all to tell bicornuate, arcuate and septate apart, there are several ways:

• Vaginal ultrasound, especially as a 3D ultrasound, is the most important tool today. In experienced hands it detects shape variations very reliably.
• Magnetic resonance imaging (MRI) is considered the gold standard when it has to be exact, for example to tell a bicornuate and a septate uterus apart safely.
• Hysteroscopy or laparoscopy come in only in individual cases, when imaging does not bring clarity.

One more tip: before anyone talks about treatment, the exact form should be established. Do not be afraid to ask which variant you have.

Does a heart-shaped uterus need to be treated?

In most cases, no. An arcuate uterus needs no treatment, and even a bicornuate uterus is usually not operated on routinely. The heart shape in itself is not a reason for surgery.

It is different for a septate uterus, the form with a dividing wall inside. If this wall leads to repeated miscarriages, it can be removed in a small procedure through a hysteroscopy. This clearly improves the chances of a successful pregnancy. That is exactly why telling the forms apart cleanly matters so much.

What you can do yourself is manageable and reassuring at the same time: know your form well, take symptoms seriously, and keep the recommended check-ups during pregnancy. In most cases that is all it takes.

When should you see a doctor?

A heart-shaped uterus is not an emergency in itself. Still, there are situations where an appointment is worth it:

• You have very heavy or very long bleeding, or period pain that limits your everyday life.
• You have an unfulfilled wish to have children over a longer period.
• You have experienced repeated miscarriages.
• You are pregnant and want to adapt your care to your situation.

In all of these cases a gynaecological practice is the right place, and for more complex questions a specialised centre. And if you feel your concerns are not being taken seriously, you may always get a second opinion. Your questions are valid, and you have a right to clear answers.

This article is for general information only and does not replace medical advice. If you have severe, unusual or persistent symptoms, please see your gynaecologist.