What difference does a year make?

[Birdspa]

I know conceiving after the age of 35 is notoriously more difficult and there can be more problems but, in your late 30's, does anyone know what difference it might make to wait until you're 39 to try for another baby instead of at 38?

Here is a chart which shows probabilities of pregnancy and infertility at different ages. As well as a higher risks of disability linked to maternal age; there's also a higher risk of multiple pregnancies.

Thank you longstory.