With chilled or frozen semen an insemination is preferably done by means of a TCI (Trans Cervical Insemination): hereby a flexible catheter is endoscopically guided through the cervix into the uterus and the semen is deposited in the uterine horn. This can be done with a female dog standing and multiple times in the same heat.
In some countries the surgical method for insemination in the uterus is still common, but there are certain disadvantages to this: the anaesthesia and surgery induce unnecessary risks and one can only do this one time during the same heat. In the Netherlands surgical insemination is considered an unethical procedure and therefore forbidden by law.
The results of the intra-uterine insemination with fresh semen are better then a natural mating. With chilled semen the results are the same as with a natural mating and in the case of frozen semen the results are a little less than with natural mating. If all factors are ok (semen quality, timing of the female etc.) the chances of a pregnancy after natural mating are about 80%.
You can watch the video of a TCI here.