Complex cyst w. septation after miscarriage

[Andy2004]

I am 29 years old and had an ultrasound at week 11 of my pregnany. We discovered that the fetus was no longer developing and that I had a cyst measuring 3 cms on my left ovary. At an ultrasound 2 weeks later the cyst measured 4.3 cms and I miscarried the following day. Six weeks later, I've had a follow-up ultrasound that showed a complex cyst with septation, but still measured the same 4.3 cms. My doctor recommends waiting and having an ultrasound in 2 months (and not trying to conceive again before that time). I am anxious about the possibility of ovarian cancer (history in my family), and am also eager to get pregnant again.
Any advice? What do you think the chances are that it's cancer? Is there still hope that it will go away on its own in 2 months - if not, why wait?
Thank you.