The reality of this world is that there are countless animals born into it that are not cared for, that live miserable lives and that are simply abused by their "owners". If there is a chance of a male dog impregnating your dog (can your dog get out of your property, or can another dog get IN? Are you planning to bring in another dog?), then you must consider everything that comes with it. Many families, especially first time dog carers or people with young children, will "get rid of" a dog simply because it is inconvenient, so finding a good home can be difficult, because people always seem "nice" when they are excited about getting a puppy and have not considered all that comes with it.
If you are willing and able to support more animals then there will be many available at rescue centers.
The other consideration is that the dog will most likely become impregnated every time she is on heat and a male has access to her, which is twice a year (depending on breed) - so aside from the practical side, there is also the strain that multiple pregnancies places on a body, especially when it gets to 4, 5, 6, and more pregnancies.
Unfortunately, any choice we make on an animal's behalf is not ideal at this stage, as there is no guarantee that we can prevent some possible harm, be it abuse from another or illness.