SO Many Multiple Births?

I had this problem up until very recently. I get notified of (and rename) all births in town, and 9 times out of 10, any given birth was twins. I had two sets of twins right after one another in my main family alone, for a total of six kids... ugh. It was brutal.

The problem went away a couple weeks ago, as abruptly as it came. Still not sure what happened or what fixed it, but I'll take it.