If the newly-formed embryo does not implant on a healthy part of the uterus, growth can be hindered and the pregnancy ended. Problems can be caused by scarring or adhesions from a previous operation, previous miscarriages or by medical conditions such as diabetes, epilepsy, thyroid, pelvic or bowel diseases.
Congenital abnormalities may also exist and these are believed to affect as many as 7% of women. For example, a uterine septum where the two halves of the uterus failed to join together properly when the uterus formed, a bicornuate uterus where there are two entirely separate cavities, or a unicornuate uterus where only one side forms properly.
Diagnosis is by 3D ultrasound scan or by more invasive techniques and treatment by surgery is possible in some cases.