I have previously reported the good news that the marriage rate and the birth rate among the most educated women has risen recently. I attribute this to more study of good sociology. :-)
Now there is evidence that the richest families are bigger. Among the top 1.5% of families by income, the proportion of 40-something women with three or more kids has risen over the past decade from 29% to 41%.
This group is too small to affect the overall birthrate very much directly. Indirectly, though, trends among the rich do tend to affect patterns among the upper middles, at least. And the rich are the people who can best afford more kids. This is a hopeful small development.