There should be a gap of at least 6 weeks between two IVF cycles. This is because the infertility specialist recommends complete rest for the recovery of the body of the woman undergoing IVF procedure. A doctor also recommends waiting till one full menstrual cycle before a patient undergo another IVF cycle. It is worth it to wait for a similar amount of time before starting with another IVF cycle.
I had one IVF cycle failure. After this, our doctor advised us to wait for a time period of 2 months before we started with the next IVF cycle. Always remember that it is suggested to wait for a significant time period before proceeding with the next cycle. The good news was that our second IVF cycle was a successful one.