A little known tip I have read about is to do with lowered milk supply caused by the return of your period. (amotherinisrael.com)
One crucial piece of false information can be blamed for the vast majority of low milk supply issues in the absence of a documented medical cause. (littleheartsbooks.com)
K, most women don't suffer from lower milk supply when their cycles return, and I've never heard of the concern you mention. (amotherinisrael.com)