Starting long protocol ivf: do you have to avoid DTD?

[totallynaive]

As per this title, I'm starting long protocol ivf this month, so I will be sniffing my nasal spray on the 4th November. Today is day 13 and my CBFM says I'm at peak fertility. Is it an absolute no-no to have one last go at conceiving naturally, or do I risk inadvertently terminating a successful pregnancy once I start with the drug treatment if I do so? My clinic doesn't start answering the phone again till Monday 9am. So - help!

YOU MUST NOT TTC IN THIS CYCLE. This is really important. There is a massive risk to an early pregnancy from the nasal spray. It switches off all the hormones that would support an early pregnancy and by the time you find out it is there it is often far too late to save it, and you have ruined your IVF cycle as well.
Please use barrier contraception from now until at least a week after your egg collection.
I've worked in IVF for 18 years and never seen a successful pregnancy from a situation like this.

Gosh, thanks freelancescientist! Wasn't likely to, and haven't tried in this cycle, but got a lastminute wobble as I didn't get advised on this by my team. Probably because I forgot to ask.

Your advice has been really timely and helpful.

Cool. Good luck with your treatment, and be nice to the embryologists

My clinic didn't tell me not to, so after a fair bit of googling, I decided to try that cycle. I understood the risks (which are as freelance mentions) but also found a number of examples online of women who had conceived on their downreg cycle and the pregnancy had continued. I understood the risks and was very alert for signs of early pregnancy. I didn't get pregnant, so it didn't matter either way.