In 1999 I was diagnosed with a unicornuate uterus.
This happened essentially by accident. I kept having unexplained pain on my right side. My doctor performed a laporoscopy (http://medical-dictionary.thefreedictionary.com/Laparoscopy) expecting to find endometrios. Instead he finds a normal looking uterus on the right side and a very absent uterus on the left side. Because my doctor had never seen this before (keep in mind that this was Dubuque, IA and that this condition is very rare - it is the most rare uterine abnormality, only affecting 1/4000 women - so I was sent to the University of Iowa Hospital for a full diagnosis.
At U of I they performed a hysterosalpingogram (HSG) (http://www.webmd.com/infertility-and-reproduction/guide/hysterosalpingogram-21590) which is an X-ray test that looks at the inside of the uterus and fallopian tubes and the area around them. There they confirmed my doctor's fears that I did indeed have a unicornuate uterus and that I most likely would never become pregnant let alone carry a child to term. I was 24, newly married (not to Mark), and had never even contemplated a life without children. It was very hard news to hear. What is the big deal you ask? The uterus is a muscle and can stretch, right? Unfortunately with a unicornuate uterus you are starting out with only about 1/3 of space of a normal uterus......and the uterus can only stretch so far. Uterine abnormalities also tend to lead to less blood flow to the uterus and less "flexibility" of the uterus in general. Uterine ruptures, hemorrhaging, miscarriages, and premature (sadly as early as 20 weeks in some cases) are all very real possibilities with a unicornuate uterus.
The good news is that I only have one horn. Many women with a unicornuate uterus also have a rudimentary, usually non-communicating horn on the other side. These tend to cause a lot of problems and often have to be removed. Also good news is that I have two functioning kidneys. The uterus and the kidneys develop from the same bundle of cells, so many women with a unicornuate uterus will only have one kidney or if they have two have only one functional kidney.
How did this happen? It is important to note that this is a congenital birth defect - I was born this way. There was nothing that I "did" to cause this to happen. Birth defects can be caused by a number of factors (http://www.medicinenet.com/birth_defects/article.htm) and most of the time the cause is really unknown. Sometimes cells just don't divide properly - that is just the way that life works.
I "showed" the doctors and was able to get pregnant twice (on the pill even). Unfortunately I have been unable to STAY pregnant for very long. Maybe it was the infertility, probably it was a lot of things, but that marriage ended not too long after the second pregnancy loss.
Flash forward to 2009 - just before I met Mark. I am at a routine visit to my gynecologist and she asks me about my fertility plans. Fertility Plans? Hadn't thought about it. I am reminded that I am steadily approaching 35 - the age at which fertility starts to take a sharp decline and is considered "geriatric" in terms of pregnancy. (http://www.ehow.com/about_5032741_geriatric-pregnancy.html)
Wow. That sucks.
We also talk about my unicornuate uterus and how that will affect my fertility. When I was younger this same doctor focused on the positive - sometimes 40% of pregnancies with a unicornuate uterus can be carried to term (term meaning 36+ weeks). Unfortunately, those statistics begin to sharply decline after 35. And, (to add insult to injury), given my history of previous pregnancy losses and the size of my uterus (teeny tiny at best), me trying to carry a child is not recommended.
At that time I thought my only chance of having a child was through adoption. The average cost for surrogacy in the US is around $100,000 (http://www.circlesurrogacy.com/costs/) and who actually has that kind of money to throw around. I am approaching that in school loan debt! OK, not quite that much, but depending on the rounding, I do have that much.