Sometimes, fertility problems begin after one or more successful pregnancies, but what happens when you experience difficulty conceiving again?
It is estimated that one in seven couples in Britain - about 3.5million people - has difficulty conceiving.
Also, a mare with a body condition score less than five will have more difficulty conceiving.
By doing so, they can improve the chances of conception in women who have difficulty conceiving after intercourse.
It is known that, 11 - 12 years before the events in the book, Marina desperately wanted children of her own but had difficulties conceiving.
The couple hopelessly yearns for a child but Bessie has difficulty conceiving a child.
As many as one in seven couples experiences difficulties conceiving.
In the past, the President has confided to acquaintances that he and his wife had difficulties conceiving their daughter, Chelsea.
In addition, Clumbers often have difficulties conceiving and giving birth, and may require caesarian sections.
A specific example is functional fixedness, which is a difficulty conceiving new uses for familiar objects.