As the mother of two boys born 13 months apart, I would definitely say more fertile - and we had fertility problems and took 2 years to get pregnant the first time! i think that once your body knows what to do, it just wants to do it again. We didn't use any protection on the basis that we wanted another child so we were prepared to take the risk, but fully expected it to take another 2 years and we didn't want too much of a gap.
I went back to work after my maternity leave already pregnant.
If you don't want another child yet, use protection!