If you increase cervical mucus you create a non-acidic environment that sperm can travel through. For women who don't produce enough cervical mucus it is the most critical step in overcoming fertility issues. This is usually overlooked by many women, but the problem with a lack of cervical mucus is that the environment actually kills off most of the viable sperm, which does not allow them to get to the egg.
If you solve all other issues related to what's preventing you from getting pregnant, but neglect this one you will always be fighting an uphill climb. It just so happens that this is actually the easiest issue to solve and enhance, and can usually be done with natural herbs, vitamins or even with a certain OTC cough medicine.