Recent signals coming from the Californian firm suggest that the Apple Watch could have a difficult 2015.

According to the Wall Street Journal the company will not follow through on a number of features that were promised to the public when the device was initially launched.

It was  pitched as a state-of-the-art health-monitoring device that would be able to measure blood pressure, heart activity and stress levels - but sources in the company have told the financial newspaper that none of these technologies have made it into the final watch.

Some of the features worked - but lacked consistency - in other cases the technology was too complex to get off the ground.

One of the WSJ's sources said that the project has become a 'blackhole' - sucking in company resources and offering little back.

According to the report the company experimented with the use of sensors that measured the conductivity of skin, and other heart-rate monitoring technologies - but the results were not stable. They could be affected by how much hair was on the users wrist, how dry their skin was, or how tight they wore the watch.

In the end they had to settle for more basic pulse-rate monitoring feature.

If the main selling point of the device is compromised - the company faces a challenge to convince users to buy the wearable.

The WJS piece describes the Apple watch as "a little bit of everything."

Its a fashion piece, it can display nuggets of information, it can communicate, and it is an activity tracker - apart from this last feature there isn't much that the watch can do that the average smartphone can't.

Apple sources say that the company is still experimenting, and hoping to have better health-tracking features in future versions of the product.

Apple has not commented on the story.

Speaking at a conference last week, Apple CEO, Tim Cook spoke about the watch, saying:

"One of the biggest surprises people are going to have when they start using it is the breadth of what it will do."

The most basic 'Sport' model, the will cost $349 (€307) - the watch is expected to go on sale in April.