Should I be preventing natural pregnancy if I'm planning on starting ivf? Age 39

3 MC, tfmr, ectopic all in the last year and half. We have consultations to start up ivf to help get a successful pregnancy but I'm wondering if I should be preventing in the mean time?

The drawback is if I have another MC i would be another month or two (or 3?!) older to start ivf. But if I have a healthy baby, I could not have to deal with the difficult ivf process... After already having been through so much. But another drawback is I could have more losses or end up with another tfmr?!

I know I can post on r/ivf but I really just wanted a perspective from people who have been in a similar situation as me.

Our tfmr was a de novo case, but it was a small genetic issue, however it is unsure whether the genetic issue caused the brain abnormalities or not..

Please, help me think through this.. It's such a hard choice and I keep going back and forth!

Ps insurance is paying for most of the IVF so cost impact is minimal. Mostly just mental at this point.