Subfertility means decreased fertility or a decreased chance of getting pregnant, but not a complete inability to get pregnant.

Someone who is described as being subfertile still has a good chance of getting pregnant on their own, but it may take longer than others.

This is compared to someone who is infertile, who needs medical assistance to get pregnant and is unlikely to get pregnant without help.

Despite this, the term subfertility is sometimes used interchangeably with the term infertility, making the term confusing when read out of context.