In the case of a vasectomy, there are a few options open to you in order to try and conceive. Potentially the simplest treatment is to use donor sperm. This is not always an option that some couples would like to take, and there are ways to attempt to obtain your partners sperm after the vasectomy. The first is to actually reverse the vasectomy, a surgical procedure that is carried out by an urologist. A potential benefit of this is that if the reversal is successful you may not need any more intervention to achieve a pregnancy. The problem though is that there are often a lot of other issues that come with that surgery that dictates the need for further treatment such as IUI or even IVF anyway. Another option is to attempt surgical sperm retrieval, again in a urology office. This will, in most cases, also require the woman to undergo an IVF cycle, but depending on the length of time since the vasectomy was originally carried out it may be more appropriate.
Yet another option would be to have the vasectomy reversed, but at the same time attempt to retrieve sperm at the same time, and freeze that sample if appropriate. In this situation if the reversal is not successful then there is the back-up of having some frozen sperm without the need for another surgery.