Regular periods after pregnancy?

Hey guys! For as long as I can remember my cycles have been super irregular ranging from 28 to 90 days. I was diagnosed with PCOS finally, after my hubby and I were TTC for a year. I ended up having 2 ectopic pregnancies (a different issue unfortunately) one after the other last year with help of Femara on the first one. And since then, even though I wasn’t pregnant for very long, all my cycles have been regular at 34 days! My RE says a regular PCOS cycle is about 35 days.

Has anybody else become more regular after being pregnant? Also, any idea why this might happen?