When we hear about something enough times, it's hard not to develop the impression that it's more common than it actually is.
For instance, while it's certainly wise to be cautious about being struck by lightning during a thunderstorm, the National Weather Service puts the odds of actually being struck in your lifetime at around one in 15,300.
By the same token, reports of people giving birth to more than five babies at once are hardly unheard of but we keep hearing about these instances because they remain exceedingly rare.
That said, I wouldn't even want to try and calculate the chances that one woman defied with her incredible pregnancy.