Unicornuate Uterus: What It Means for Fertility, Miscarriage, and Pregnancy
Have you been diagnosed with a unicornuate uterus and are wondering what this means for your fertility and pregnancy risks? You may have heard of other uterine anomalies like a bicornuate uterus, a septate uterus, or an arcuate uterus and are curious if these could be the cause of your infertility and miscarriage problems. In this in-depth article, we'll cover everything you need to know about unicornuate uterus - what it is, how common it is, diagnosis and treatment options, and most importantly, what it can mean for your fertility and pregnancy outcomes.
What is a Unicornuate Uterus?
A unicornuate uterus is a rare, but not uncommon, uterine anomaly that occurs when the uterus fails to fully develop during embryonic formation. Normally, the uterus forms from two separate uterine horns that fuse together, creating the familiar pear-shaped organ. However, in the case of a unicornuate uterus, only one of these uterine horns fully develops, resulting in a uterus that is smaller and shaped more like a banana.
There are several different types of unicornuate uterus that can occur:
No horn: Only one side of the uterus develops, with no remnant of the other side.
Communicating: A small, underdeveloped second horn is present, but it has a uterine lining that can shed during menstruation.
Non-communicating: A small, underdeveloped second horn is present, but it does not have a uterine lining and cannot shed.
Non-communicating with a rudimentary horn: A small, underdeveloped second horn is present and has a uterine lining, but it has no outlet for menstrual flow, which can cause pain.
These variations in unicornuate uterus can impact a person's fertility, pregnancy risks, and treatment options in different ways.
How Common is a Unicornuate Uterus?
Unicornuate uterus is a relatively rare condition, affecting approximately 1 in 1,000 people with a uterus. However, the true prevalence may be higher, as some people with a unicornuate uterus may never be diagnosed if they don't experience any fertility or pregnancy complications.
The difficulty in diagnosing unicornuate uterus is that some people may have no symptoms or issues at all, while others may only discover they have the condition during an evaluation for infertility or complications in pregnancy. As Dr. Lora Shahine explains, "Some people might not get diagnosed until later in life, sometimes never, because they have no reason to have imaging of their uterus or there's no fertility or pregnancy problems. There's no symptoms."
Diagnosing a Unicornuate Uterus
Unicornuate uterus is typically diagnosed through imaging tests, such as:
Pelvic ultrasound: This is often the first-line imaging test used to evaluate the uterus and can sometimes identify a unicornuate uterus.
Hysterosalpingogram (HSG): This X-ray procedure involves injecting dye into the uterus and fallopian tubes to assess their structure and function.
Pelvic MRI: This more advanced imaging test can provide detailed images of the uterus and other pelvic organs.
In some cases, a unicornuate uterus may also be discovered during a surgical procedure, such as a laparoscopy, when the uterus is directly examined.
If you suspect you may have a uterine anomaly, be sure to ask your healthcare provider about getting the appropriate imaging tests. As Dr. Shahine recommends, "Sometimes people will have surgery for whatever reason, a laparoscopy, and if the uterus is examined, people will say, 'Oh, this is not a normal uterus. We actually only have one side that's available.'"
Impact on Fertility
The impact of a unicornuate uterus on fertility can vary greatly from person to person. While some individuals with this condition may have no trouble conceiving and carrying a pregnancy to term, others may experience fertility challenges.
According to a 2018 study by Chen et al., approximately 23.7% of people with a unicornuate uterus may have difficulty getting pregnant. The reasons for this are not entirely clear, but theories include:
Implantation issues due to a thinner uterine lining
Increased risk of ectopic pregnancy (a pregnancy that implants outside the uterus)
Higher rates of recurrent miscarriage, potentially due to the uterus being unable to fully support a growing fetus
It's important to note, however, that not everyone with a unicornuate uterus will face fertility problems. As Dr. Shahine emphasizes, "There are people that have had full-term gorgeous pregnancies and deliveries with no complications with a unicornuate uterus."
If you have been diagnosed with a unicornuate uterus and are struggling to conceive, consider reaching out to a fertility specialist who can help evaluate your specific situation and discuss potential treatment options, such as assisted reproductive technologies like in vitro fertilization (IVF).
Pregnancy Risks with a Unicornuate Uterus
Individuals with a unicornuate uterus may face an increased risk of certain pregnancy complications, though the severity can vary. Some of the potential risks include:
Preterm labor: A 2011 study by Chan et al. found that up to 50% of pregnancies in people with a unicornuate uterus resulted in preterm delivery (before 37 weeks gestation).
Miscarriage: There may be a higher risk of miscarriage, particularly in the first trimester, due to the uterus's inability to fully support a growing fetus.
Fetal growth restriction: The baby may not grow as expected due to the limited space and blood supply in the unicornuate uterus.
Placental complications: Issues like placental abruption (when the placenta separates from the uterine wall) may be more common.
However, it's important to remember that not everyone with a unicornuate uterus will experience these complications. As Dr. Shahine notes, "There are people that have had full-term gorgeous pregnancies and deliveries with no complications with a unicornuate uterus."
If you have a unicornuate uterus and become pregnant, your healthcare provider will likely monitor you more closely throughout your pregnancy, looking for any signs of preterm labor, fetal growth issues, or placental problems. In some cases, you may be referred to a high-risk obstetrician or maternal-fetal medicine specialist for additional care and support.
Treatment Options for a Unicornuate Uterus
While the unicornuate uterus itself cannot be surgically "fixed," there are some treatment options that may be considered depending on your specific situation and symptoms:
Removal of a non-communicating horn: If you have a non-communicating horn that is causing pain or other symptoms, it may be surgically removed to alleviate those issues.
Assisted reproductive technologies: For those with fertility challenges, options like in vitro fertilization (IVF) may be used to help with conception. The embryo can then be transferred directly into the functioning uterine cavity.
Gestational carrier: In some cases, such as with the influencer Selena Speaky Boo, individuals with a unicornuate uterus may choose to use a gestational carrier to carry their pregnancy.
Closer monitoring during pregnancy: If you become pregnant with a unicornuate uterus, your healthcare provider will likely monitor you more closely, looking for any signs of preterm labor, fetal growth issues, or placental problems.
It's important to work closely with your healthcare team to determine the best course of action for your individual needs and goals. As Dr. Shahine advises, "If you get this diagnosis, here are some questions I recommend that you ask your doctor: How will a unicornuate uterus impact my fertility? Are there any additional tests I should get? What are my treatment options if I want to conceive? What steps should I take to ensure a safe pregnancy? Should I have a consult with specialists?"
Stay Informed and Advocate for Your Care
A unicornuate uterus diagnosis can be overwhelming, but knowledge is power. By understanding this condition, its potential impacts, and the available treatment options, you can be better equipped to advocate for your reproductive health and make informed decisions about your care.
By staying informed, advocating for your needs, and working closely with your healthcare team, you can navigate the unique challenges of a unicornuate uterus and take steps towards achieving your reproductive goals.
For more insights and resources from Dr. Lora Shahine, be sure to check out her newsletter, listen to her Brave & Curious podcast, and follow her on Instagram, TikTok, Twitter, and Facebook. And don't hesitate to reach out to specialists like reproductive endocrinologists and high-risk obstetricians who can guide you through this journey.
