No date available; my money is on the late 40s or early 50s.
Incredibly, this is not an ad rejoicing that The Crazy Bitch Wife can finally get back to her wifely duties like fixin' a Hungry Hubby his morning sausage and eggs.
No, it seems as though Mornidine was a drug prescribed for morning sickness. That's right. Morning sickness. Mornidine...get it now? You know, because a trivial matter like being deathly ill during the gestation of your child is no reason for Hubby to have to go without his pigs in a blanket.
Mornidine was taken off the market on July 17, 1969. It was deemed to be dangerous, or something. I suspect Flipper Babies, or possibly babies being born as Acid Freaks, but am unable to find much about its removal from the market on The Internets.
Furthermore, the evidence as to how American Breakfasts suffered as a result is anecdotal, at best.