I know this is just one person's story but maybe it will help you feel better
During my pregnancy with ds I had 3 ultrasounds (one at about 4 weeks, one at 7 or 8 weeks and one at 20 weeks). NONE of them showed anything abnormal. DS was carried to term (born at 39 weeks exactly but was kicked out due to pre-e). He had none of the birth defects mentioned in this article.
Fastforward about 4 years. Different state, different doctors. I had an IUD inserted. Due to issues with it I decided to have it removed about 2 months later. Doctor couldn't find it. Sent me for an u/s where the tech mentions that I have a "double uterus". That was news to me! LOL! This article talks about bicornuate uterus, which is slightly different in the shape (bicornuate is more heart shaped, from what I understand, whereas uterus didelphis is the double uterus).
While it does say the risks are slightly higher, that doesn't mean it will happen to you