The Apple iPhone 4S, released October last year, didn’t differ from its predecessors in the sense that it took the mobile phone market by storm. And the numbers show just as much, with several marketing research companies showing the iPhone 4S as their best-selling smartphone. Also, Apple’s iOS platform is nipping at the heels of Android in terms of operating systems.

However, is the iPhone mania indeed bound to die down a bit in the first quarter of the year?

According to Gartner, the iPhone’s sales may finally slow down in Q1 2012 because of two main factors. The first would be the current American economic situation which still is not very good. Second would be consumer trends – with many more buyers willing to wait for the iPhone 4S, Gartner is predicting this too would lead to reduced iPhone sales early in the year.

In addition to the two possibilities, the number of Android smartphones shipping with the latest 4.0 Ice Cream Sandwich platform may also take a bite out of Apple’s market share.

With the 2012 Mobile World Congress fast approaching and a variety of new handsets ready to be unveiled, the brain trust behind Apple had better hope the iPhone 4S’ sensational sales hold up.

Speaking of operating systems, a new version of iOS has yet to be released, and even smaller competitors – in terms of market share – like Microsoft are ramping up their efforts, especially with Nokia set to release the first-ever LTE capable Windows Phone before the quarter ends.