Bugger - just lost a post!

It is possible to fall pg if you DTD on the last day of AF - but unlikely. Sperm can survive for 7-10 days in perfect conditions so depending on how long AF was it is theoretically possible.

But, if conception occurred on the last day of AF then I can't see how it could possibly result in a pregnancy because on the last day of AF your hormones would be a bit whacked to start with but there is no uterus lining for the egg can implant into ITKWIM.